CN110605967A - Auxiliary brake control method and device for heavy-duty vehicles - Google Patents

Abstract

The invention discloses an auxiliary braking control method and device for a heavy-duty car, which can obtain running parameters related to car braking; comparing the operating parameters with conditions for entering the braking modes, each braking mode corresponding to at least one braking device, the braking device of the vehicle comprising: the system comprises an engine, a motor and a hydraulic retarder; and when the operation parameters meet the condition of entering one of the braking modes, controlling the braking device corresponding to the braking mode to perform auxiliary braking. The invention judges under what condition, adopts one or more auxiliary braking devices corresponding to the condition to ensure that the braking effect is optimal.

Description

Auxiliary brake control method and device for heavy-duty vehicles

technical field

The invention relates to the field of vehicle control, in particular to an auxiliary braking control method and device for heavy vehicles.

Background technique

During the daily driving of heavy-duty vehicles, if they are driving on smooth road conditions, the service brakes can generally meet the braking requirements. However, under full-load road conditions with long slopes, in order to avoid the vehicle from continuously accelerating to a dangerous speed under the action of its own gravity, if only the service brake is used for continuous braking to achieve the purpose of stabilizing the vehicle speed, it may cause the service brake to work for a long time and cause temperature. If the value is too high, the braking effect will drop sharply or even fail, which will pose a hidden danger to driving safety.

Now, through auxiliary braking equipment such as engines, motors, and hydraulic retarders, it is possible to achieve the effect of using less or no service brakes for heavy vehicles to keep the speed of the vehicle low or stable. However, the prior art cannot judge which one or more braking devices are used to achieve the best braking effect under which circumstances.

Contents of the invention

In view of this, the present invention provides an auxiliary braking control method and device for heavy-duty vehicles, with the purpose of judging which one or more braking devices to use in that situation to achieve the best braking effect.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The first aspect of the present invention discloses an auxiliary braking control method for heavy vehicles, including:

Obtain the operating parameters related to the braking of the vehicle, the operating parameters include the brake pedal opening, the state of the auxiliary brake operating handle, the braking power required by the heavy vehicle, the speed of the heavy vehicle, the ratio of battery power and the acceleration of the heavy vehicle at least One, wherein the battery power ratio is the ratio of the actual remaining power of the car to the total power;

Comparing the operating parameters with the conditions for entering each braking mode, each braking mode corresponds to at least one braking device, and the braking device of the automobile includes: an engine, a motor, and a hydraulic retarder;

When the operating parameters meet the conditions for entering one of the braking modes, the braking device corresponding to the braking mode is controlled to perform auxiliary braking.

Optionally, when the operating parameters meet the conditions for entering one of the braking modes, the braking device corresponding to the braking mode is controlled to perform auxiliary braking, including:

When the operating parameters meet the conditions for entering the motor regenerative braking mode, the motor is controlled to provide braking power for auxiliary braking;

Wherein, the conditions for entering the regenerative braking mode of the motor include: at least one of the first condition, the second condition, the third condition and the fourth condition,

The first condition is: the state of the auxiliary brake handle is open and the opening of the brake pedal is smaller than the second opening limit and the braking power required by the heavy-duty vehicle is not greater than the rated power of the motor;

The second condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is less than a third opening limit and the speed of the heavy vehicle is less than a first speed limit;

The third condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is not less than the third opening limit and the braking power required by the heavy-duty vehicle is not greater than the rated power of the motor;

The fourth condition is: the state of the auxiliary brake handle is off, the speed of the heavy-duty vehicle is not less than the first speed limit, and the braking power required by the heavy-duty vehicle is not greater than the rated power of the motor.

Optionally, when the operating parameters meet the conditions for entering one of the braking modes, the braking device corresponding to the braking mode is controlled to perform auxiliary braking, including:

When the operating parameters meet the conditions for entering the engine-motor combined braking mode, the engine and the motor are controlled to jointly provide braking power for auxiliary braking;

Wherein, the conditions for entering the engine-motor combined braking mode include: at least one of the fifth condition, the sixth condition and the seventh condition,

The fifth condition is: the state of the auxiliary brake operating handle is open and the opening of the brake pedal is not greater than the second limit value and the braking power required by the heavy-duty vehicle is greater than the rated power of the motor;

The sixth condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is not less than the third opening limit and the braking power required by the heavy-duty vehicle is greater than the rated power of the motor;

The seventh condition is: the state of the auxiliary brake handle is closed, the speed of the heavy-duty vehicle is not less than the first speed limit, and the braking power required by the heavy-duty vehicle is greater than the rated power of the motor.

Optionally, when the operating parameters meet the conditions for entering one of the braking modes, controlling the braking device corresponding to the braking mode to perform auxiliary braking also includes:

After the heavy-duty vehicle enters the motor regenerative braking mode, when the operating parameters meet the conditions for entering the engine auxiliary braking mode from the motor regenerative braking mode, the engine is controlled to provide braking power for auxiliary braking;

Wherein, the conditions for entering the engine auxiliary braking mode from the motor regenerative braking mode include: the eighth condition,

The eighth condition is: the battery power ratio is greater than a first power limit.

Optionally, when the operating parameters meet the conditions for entering one of the braking modes, controlling the braking device corresponding to the braking mode to perform auxiliary braking also includes:

After the heavy-duty vehicle enters the engine-motor combined braking mode for a preset period of time, when the operating parameters meet the conditions for entering the engine-motor-hydraulic retarder combined braking mode from the engine-motor combined braking mode, then Control the engine, motor and hydraulic retarder to jointly provide braking power for auxiliary braking;

Wherein, the conditions for entering the engine-motor-hydraulic retarder combined braking mode from the engine-motor combined braking mode include: the ninth condition,

The ninth condition is: the acceleration of the heavy vehicle is greater than the first acceleration limit.

Optionally, when the operating parameters meet the conditions for entering one of the braking modes, controlling the braking device corresponding to the braking mode to perform auxiliary braking also includes:

After the heavy-duty vehicle enters the engine-motor-hydraulic retarder joint braking mode for a preset period of time, when the operating parameters meet the conditions for increasing the opening of the hydraulic retarder solenoid valve, the hydraulic retarder is controlled. Increase the opening of the electromagnetic valve of the actuator to provide greater braking power for auxiliary braking;

Wherein, the conditions for increasing the opening of the solenoid valve of the hydraulic retarder include: the tenth condition,

The tenth condition is: the acceleration of the heavy vehicle is greater than the second acceleration limit.

Optionally, when the operating parameters meet the conditions for entering one of the braking modes, the braking device corresponding to the braking mode is controlled to perform auxiliary braking, including:

When the operating parameters meet the conditions for entering the engine-hydraulic retarder combined braking mode, the engine and the hydraulic retarder are controlled to jointly provide braking power for auxiliary braking;

Wherein, the conditions for entering the engine-hydraulic retarder combined braking mode include: the eleventh condition,

The eleventh condition is: the brake pedal opening is greater than a first opening limit.

Optionally, when the operating parameters meet the conditions for entering one of the braking modes, the braking device corresponding to the braking mode is controlled to perform auxiliary braking, including:

When the operating parameters meet the conditions for entering the engine auxiliary braking mode, the engine is controlled to provide braking power for auxiliary braking;

Wherein, the conditions for entering the engine auxiliary braking mode include: the twelfth condition,

The twelfth condition is: the state of the auxiliary operation brake handle is open and the brake pedal opening is not greater than the first opening limit and the brake pedal opening is greater than the second opening limit, Wherein the first opening limit is greater than the second opening limit.

The second aspect of the present invention discloses an auxiliary brake control device for a heavy-duty vehicle. The device includes: an acquisition unit, a comparison unit and a control unit,

The acquiring unit is used to acquire the operating parameters related to the braking of the vehicle, the operating parameters include the opening of the brake pedal, the state of the auxiliary brake operating handle, the braking power required by the heavy vehicle, the speed of the heavy vehicle, and the battery power ratio And at least one of the heavy-duty vehicle acceleration, wherein the battery power ratio is the ratio of the actual remaining power of the car to the total power;

The comparison unit is used to compare the operating parameters with the conditions for entering each braking mode, and each braking mode corresponds to at least one braking device, and the braking device of the automobile includes: an engine, a motor, and a hydraulic brake accelerator;

The control unit is configured to control the braking device corresponding to the braking mode to perform auxiliary braking when the operating parameters meet the conditions for entering one of the braking modes.

Optionally, the control unit includes: a first control subunit,

The first control subunit is configured to control the motor to provide braking power for auxiliary braking when the operating parameters meet the conditions for entering the motor regenerative braking mode;

Wherein, the conditions for entering the regenerative braking mode of the motor include: at least one of the first condition, the second condition, the third condition and the fourth condition,

The first condition is: the state of the auxiliary brake handle is open and the opening of the brake pedal is smaller than the second opening limit and the braking power required by the heavy-duty vehicle is not greater than the rated power of the motor;

The second condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is less than a third opening limit and the speed of the heavy vehicle is less than a first speed limit;

The third condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is not less than the third opening limit and the braking power required by the heavy-duty vehicle is not greater than the rated power of the motor;

The fourth condition is: the state of the auxiliary brake handle is off, the speed of the heavy-duty vehicle is not less than the first speed limit, and the braking power required by the heavy-duty vehicle is not greater than the rated power of the motor.

Optionally, the control unit includes: a second control subunit,

The second control subunit is configured to control the engine and the motor to jointly provide braking power for auxiliary braking when the operating parameters meet the conditions for entering the engine-motor combined braking mode;

Wherein, the conditions for entering the engine-motor combined braking mode include: at least one of the fifth condition, the sixth condition and the seventh condition,

The fifth condition is: the state of the auxiliary brake operating handle is open and the opening of the brake pedal is not greater than the second limit value and the braking power required by the heavy-duty vehicle is greater than the rated power of the motor;

The sixth condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is not less than the third opening limit and the braking power required by the heavy-duty vehicle is greater than the rated power of the motor;

The seventh condition is: the state of the auxiliary brake handle is closed, the speed of the heavy-duty vehicle is not less than the first speed limit, and the braking power required by the heavy-duty vehicle is greater than the rated power of the motor.

Optionally, the control unit further includes: a third control subunit,

The third control subunit is used to control the engine to provide braking when the operating parameters meet the conditions for entering the engine auxiliary braking mode from the motor regenerative braking mode after the heavy-duty vehicle enters the motor regenerative braking mode. power for auxiliary braking;

Wherein, the conditions for entering the engine auxiliary braking mode from the motor regenerative braking mode include: the eighth condition,

The eighth condition is: the battery power ratio is greater than a first power limit.

Optionally, the control unit further includes: a fourth control subunit,

The fourth control subunit is used for the heavy-duty vehicle to enter the engine-motor combined braking mode for a preset period of time, when the operating parameters meet the requirements of entering the engine-motor-hydraulic retarding mode from the engine-motor combined braking mode When the conditions of combined braking mode of the brake are controlled, the engine, the motor and the hydraulic retarder are controlled to jointly provide braking power for auxiliary braking;

Wherein, the conditions for entering the engine-motor-hydraulic retarder combined braking mode from the engine-motor combined braking mode include: the ninth condition,

The ninth condition is: the acceleration of the heavy vehicle is greater than the first acceleration limit.

Optionally, the control unit further includes: a fifth control subunit,

The fifth control subunit is used for shifting the gear up when the operating parameters meet the requirements of the solenoid valve opening of the hydraulic retarder after the heavy-duty vehicle enters the engine-motor-hydraulic retarder combined braking mode for a preset period of time When the conditions are met, the hydraulic retarder solenoid valve opening is controlled to increase gears to provide greater braking power for auxiliary braking;

Wherein, the conditions for increasing the opening of the solenoid valve of the hydraulic retarder include: the tenth condition,

The tenth condition is: the acceleration of the heavy vehicle is greater than the second acceleration limit.

Optionally, the control unit includes: a sixth control subunit,

The sixth control subunit is used to control the engine and the hydraulic retarder to jointly provide braking power for auxiliary braking when the operating parameters meet the conditions for entering the engine-hydraulic retarder combined braking mode ;

Wherein, the conditions for entering the engine-hydraulic retarder combined braking mode include: the eleventh condition,

The eleventh condition is: the brake pedal opening is greater than a first opening limit.

Optionally, the control unit includes: a seventh control subunit,

The seventh control subunit is configured to control the engine to provide braking power for auxiliary braking when the operating parameters meet the conditions for entering the engine auxiliary braking mode;

Wherein, the conditions for entering the engine auxiliary braking mode include: the twelfth condition,

The twelfth condition is: the state of the auxiliary operation brake handle is open and the brake pedal opening is not greater than the first opening limit and the brake pedal opening is greater than the second opening limit, Wherein the first opening limit is greater than the second opening limit.

The invention provides an auxiliary braking control method and device for heavy-duty vehicles, which can obtain operating parameters related to vehicle braking; compare the operating parameters with the conditions for entering each braking mode, and each braking mode corresponds to at least one The braking device of the car includes: the engine, the motor and the hydraulic retarder; when the operating parameters meet the conditions for entering a braking mode in each braking mode, the braking device corresponding to the braking mode is controlled to assist brake. The present invention judges under what circumstances, adopts one or more auxiliary braking devices corresponding to the circumstances, so as to achieve the best braking effect.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings that are required in the description of the embodiments or the prior art.

Fig. 1 is a schematic flow chart of an auxiliary braking control method for a heavy-duty vehicle provided by an embodiment of the present invention;

Fig. 2 is a conditional logic judgment diagram for a heavy-duty vehicle entering each braking mode provided by an embodiment of the present invention;

3 is a conditional logic judgment diagram for a heavy-duty vehicle entering the engine auxiliary braking mode from the motor braking recovery mode provided by the embodiment of the present invention;

Fig. 4 is a schematic diagram of connections between auxiliary braking devices provided by an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of an auxiliary braking control device for a heavy-duty vehicle provided by an embodiment of the present invention.

Detailed ways

The invention discloses an auxiliary braking control method and device for a heavy-duty vehicle. Those skilled in the art can learn from the content of this article and appropriately improve the process parameters to realize it. In particular, it should be pointed out that all similar replacements and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and the relevant personnel can obviously make changes or appropriate changes and combinations to the method and application described herein without departing from the content, spirit and scope of the present invention to realize and Apply the technology of the present invention.

When a heavy-duty vehicle is fully loaded on a long slope, in order to prevent the vehicle from continuously accelerating to a dangerous speed under the action of its own gravity, it adopts service braking and/or auxiliary braking. When the current technology cannot judge the situation through the heavy-duty vehicle control system, what kind of auxiliary braking strategy should be adopted to achieve the best. Now, judging and judging the auxiliary braking method is mainly judged by the driver himself, resulting in that the braking effect cannot reach the best or ideal state, and often only one auxiliary braking method is adopted by the driver's judgment, and each auxiliary braking method Each driving method has its limitations, and the same service brake has its limitations, as follows:

Service brake: The friction between the fixed part and the rotating part is used to generate the braking torque. When the heavy vehicle goes down a long slope, the frequent use of the service brake for a long time will cause the temperature of the friction plate to rise, resulting in a decline in braking performance or even failure. The water spraying device commonly used in the market can effectively reduce the heat attenuation of the brake pads and prolong the service life of the service brake by spraying water on the friction plates to cool down. The user installs the sprinkler device by himself, which is low in cost and does not require additional operations, and only needs to add water regularly.

However, it will increase the frequency of brake replacement and increase user costs. Although installing sprinklers can prolong the service life of brakes, using sprinklers in winter can easily cause roads to freeze and rollover accidents can easily occur, causing serious safety hazards. Currently, sprinklers have gradually become a special treatment item for traffic control departments.

Engine-assisted braking: Stop the fuel supply to the engine of the moving vehicle, keep in gear and coast, and the vehicle drives the engine crankshaft to continue to rotate through the drive wheels, rear axle, and transmission to consume a certain amount of kinetic energy. On this basis, add a set of devices to the engine to increase the friction consumption and energy consumption in the working stroke of the engine, and force the engine to reduce the speed, so as to achieve the purpose of reducing the speed of the vehicle in a short time.

It can basically meet the needs of most braking conditions of users, but in the case of high-speed vehicles, heavy loads and relatively steep slopes, limited by the limited braking power provided by the engine, it is still not enough to fully provide the braking power required by heavy-duty vehicles .

Braking with hydraulic retarder: When the vehicle needs to brake under long slope conditions, the retarder housing is filled with working fluid, and the vehicle drives the rotating impeller to rotate with the output shaft through the driving wheel, rear axle and transmission Drive the rotation of the working fluid, apply torque to the fixed impeller and the casing, the fixed impeller generates a reaction force on the working fluid and transmits it to the rotating impeller, and then transmits it to the driving wheel to achieve the purpose of vehicle deceleration.

It can provide sufficient braking power, but the working process of the hydraulic retarder is to convert the kinetic energy of the vehicle into heat energy and dissipate it through the cooling system of the heavy-duty vehicle. The impact should not be too large. At the same time, the hydraulic retarder provides braking power, and the driver still manually selects the gear according to the actual road conditions. Under different vehicle speeds, vehicle weights and slopes, the required braking power is different, which increases the difficulty of driving. In addition, the hydraulic retarder and the engine generally use the same set of cooling system. If the water temperature of the cooling system of the heavy-duty vehicle is too high, the hydraulic retarder will not be able to achieve the desired braking effect.

Motor recuperation braking: The heavy-duty vehicle control system sends the required negative torque to the motor through the braking Map, and the motor becomes the power generation mode. Generate braking torque, at this time the kinetic energy of the vehicle is converted into electrical energy, which is stored in the power battery for use in driving conditions.

However, limited by the power of the motor, it can run for a long time under the rated power of the motor. After the rated power of the motor is exceeded, the running time is limited and the braking power that can be provided is limited.

Therefore, the present invention proposes an auxiliary braking control method and device for heavy-duty vehicles, which can determine under what circumstances and adopt one or more auxiliary braking devices corresponding to the situation to achieve the best braking effect.

As shown in FIG. 1, an auxiliary braking control method for a heavy-duty vehicle provided in an embodiment of the present invention includes:

Step S101: Obtain operating parameters related to vehicle braking.

It should be noted that the operating parameters include at least one of the opening degree of the brake pedal, the state of the auxiliary brake operating handle, the braking power required by the heavy vehicle, the speed of the heavy vehicle, the ratio of battery power, and the acceleration of the heavy vehicle.

Among them, the brake pedal opening is the brake pedal stepping degree, expressed as a percentage, the higher the brake pedal opening is, the greater the required braking power is;

The state of the auxiliary brake operating handle is divided into open and closed;

The braking power required by the heavy-duty vehicle is calculated according to the formula P=FV=(F1+F2+F3+ma)V, where P is the braking power required by the heavy-duty vehicle, F1 is the frictional resistance between the heavy-duty vehicle and the ground, F2 is the air resistance (wind resistance) of the heavy-duty vehicle, F3 is the slope resistance of the heavy-duty vehicle when driving on the slope, m is the mass of the heavy-duty vehicle, a is the acceleration of the heavy-duty vehicle, and V is the speed of the heavy-duty vehicle;

The battery power ratio is the ratio of the actual remaining power of the car to the total power.

Step S102: comparing the operating parameters with the conditions for entering each braking mode.

It should be noted that each braking mode corresponds to at least one braking device, and the braking device of a car includes: an engine, a motor, and a hydraulic retarder.

Step S103: When the operating parameters meet the conditions for entering one of the braking modes, control the braking device corresponding to the braking mode to perform auxiliary braking.

Optionally, in a specific embodiment, when the operating parameters meet the conditions for entering the motor regenerative braking mode, the motor is controlled to provide braking power for auxiliary braking;

Wherein, the conditions for entering the regenerative braking mode of the motor include: at least one of the first condition, the second condition, the third condition and the fourth condition,

The first condition is: the state of the auxiliary brake handle is open and the opening of the brake pedal is less than the second opening limit and the braking power required by the heavy-duty vehicle is not greater than the rated power of the motor;

The second condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is less than the third opening limit and the speed of the heavy-duty vehicle is less than the first speed limit;

The third condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is not less than the third opening limit and the braking power required by the heavy-duty vehicle is not greater than the rated power of the motor;

The fourth condition is: the state of the auxiliary brake handle is off, the speed of the heavy vehicle is not less than the first speed limit, and the braking power required by the heavy vehicle is not greater than the rated power of the motor.

Optionally, after the heavy-duty vehicle enters the motor regenerative braking mode, when the operating parameters meet the conditions for entering the engine auxiliary braking mode from the motor regenerative braking mode, the engine is controlled to provide braking power for auxiliary braking;

Among them, the conditions for entering the engine auxiliary braking mode from the motor recovery braking mode include: the eighth condition,

The eighth condition is: the battery power ratio is greater than the first power limit. Optionally, in a specific embodiment, when the operating parameters meet the conditions for entering the engine-motor combined braking mode, the engine and the motor are controlled to jointly provide braking power for auxiliary braking;

Wherein, the conditions for entering the engine-motor combined braking mode include: at least one of the fifth condition, the sixth condition and the seventh condition,

The fifth condition is: the state of the auxiliary brake operating handle is open and the opening of the brake pedal is not greater than the second limit value and the braking power required by the heavy-duty vehicle is greater than the rated power of the motor;

The sixth condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is not less than the third opening limit and the braking power required by the heavy-duty vehicle is greater than the rated power of the motor;

The seventh condition is: the state of the auxiliary brake handle is off, the speed of the heavy vehicle is not less than the first speed limit, and the braking power required by the heavy vehicle is greater than the rated power of the motor.

Optionally, after the heavy-duty vehicle enters the engine-motor combined braking mode for a preset period of time, when the operating parameters meet the conditions for entering the engine-motor-hydraulic retarder combined braking mode from the engine-motor combined braking mode, then Control the engine, motor and hydraulic retarder to jointly provide braking power for auxiliary braking;

Among them, the conditions for entering the engine-motor-hydraulic retarder combined braking mode from the engine-motor combined braking mode include: the ninth condition,

The ninth condition is: the acceleration of the heavy vehicle is greater than the first acceleration limit.

Optionally, after the heavy-duty vehicle enters the engine-motor-hydraulic retarder combined braking mode for a preset period of time, when the operating parameters meet the conditions for increasing the opening of the hydraulic retarder solenoid valve, the hydraulic retarder is controlled Increase the opening of the electromagnetic valve of the actuator to provide greater braking power for auxiliary braking;

Among them, the conditions for increasing the opening of the solenoid valve of the hydraulic retarder include: the tenth condition,

The tenth condition is: the acceleration of the heavy vehicle is greater than the second acceleration limit.

Optionally, in a specific embodiment, when the operating parameters meet the conditions for entering the engine-hydraulic retarder combined braking mode, the engine and the hydraulic retarder are controlled to jointly provide braking power for auxiliary braking;

Among them, the conditions for entering the engine-hydraulic retarder combined braking mode include: the eleventh condition,

The eleventh condition is: the brake pedal opening is greater than the first opening limit.

Optionally, in a specific embodiment, when the operating parameters meet the conditions for entering the engine auxiliary braking mode, the engine is controlled to provide braking power for auxiliary braking;

Among them, the conditions for entering the engine auxiliary braking mode include: the twelfth condition,

The twelfth condition is: the state of the auxiliary operation brake handle is open and the brake pedal opening is not greater than the first opening limit and the brake pedal opening is greater than the second opening limit, wherein the first opening limit is greater than The second opening limit.

It should be noted that the first opening limit>the second opening limit>the third opening limit, and the first acceleration limit>the second acceleration limit. Optionally, in a specific embodiment, the logical judgment conditions for using each auxiliary braking device are as shown in Figure 2:

In Figure 2, A1 is the first opening limit, A2 is the second opening limit, A3 is the third opening limit, V1 is the first speed limit, B1 is the first acceleration limit, B2 is the second Two acceleration limits, P1 represents the braking power required by heavy-duty vehicles, and P2 represents the rated power of the motor.

It should be noted that the first opening limit>the second opening limit>the third opening limit, and the first acceleration limit>the second acceleration limit.

Step S201: Determine whether the opening of the brake pedal is greater than A1. A1 is a relatively large value, close to 100%. If the opening of the brake pedal is greater than A1, it means that the heavy-duty vehicle is in an emergency braking situation. Even if there is no auxiliary handle signal, the engine and the hydraulic retarder will also be used for joint braking, that is, the engine-hydraulic retarder combined braking mode will be entered, and the service brake will also take effect to ensure driving safety. If not, proceed to the steps S202.

Step S202: Determine whether the auxiliary brake operating handle is on, if yes, go to step S203, if not, go to step S204, wherein when the auxiliary brake handle is on, it means that the heavy vehicle is going down a long slope.

Step S203: Determine whether the opening of the brake pedal is greater than A2, if yes, use the engine for braking, that is, enter the engine-assisted braking mode, if not, proceed to step S205.

Step S204: Determine whether the brake pedal opening is less than A3 and the vehicle speed is less than V1. If both are yes, it means that the braking power required by the vehicle is relatively small, and the motor is sufficient to provide the braking power required by the heavy-duty vehicle. Then use Motor regenerative braking, that is, enter the motor regenerative braking mode, and if at least one of them is negative, go to step S205.

Step S205: Determine whether P1 is greater than P2. If so, it means that the braking power required by the heavy-duty vehicle exceeds the rated power of the motor. At this time, the motor and the engine are used to provide braking power at the same time, that is, the engine-motor combined braking mode is entered; if not, It means that the braking power required by the heavy-duty vehicle does not exceed the rated power of the motor. At this time, the motor is used to provide the braking power, that is, the motor regenerative braking mode is entered.

Step S206: After the heavy-duty vehicle enters the engine-motor combined braking mode for a preset period of time, determine whether the acceleration of the heavy-duty vehicle is greater than B1. If so, it means that the heavy-duty vehicle cannot run smoothly, and the power provided by the motor and the engine together does not meet the requirements of the heavy-duty vehicle. Braking power, at this time, control the hydraulic retarder solenoid valve to open, that is, enter the engine-motor-hydraulic retarder combined braking mode, if not, end.

Step S207: After the heavy-duty vehicle enters the engine-motor-hydraulic retarder joint braking mode for a preset period of time, determine whether the acceleration of the heavy-duty vehicle is less than B1, if not, it means that the braking power provided still does not meet the braking power required by the heavy-duty vehicle. Dynamic power, at this time, control the opening of the hydraulic retarder solenoid valve to increase the gear, if so, then end.

As shown in Figure 3, in Figure 3, SOC is the ratio of battery power, and S1 is the first power limit, where the first power limit is a higher limit, indicating that the power reaches the preset value and cannot continue to charge.

In the embodiment in Fig. 2, step S301 is also included: in all the above-mentioned modes, when the motor provides braking power, it is judged whether the motor battery power ratio SOC is greater than S1, if it is, it means that the battery cannot recover more power, here This part of the braking power provided by the motor is changed to be provided by the engine, if not, the motor will continue to provide the automatic power it needs to provide.

The connection between auxiliary braking equipment and heavy-duty vehicle equipment is shown in Figure 4, where VCU represents the heavy-duty vehicle control system, ECU represents the engine controller, and MCU represents the motor controller.

The VCU directly or indirectly controls the engine, motor and hydraulic retarder to provide braking power, thereby affecting the transmission, then to the drive shaft, then to the rear axle, and finally to the driving wheels to realize the change of the speed of the heavy-duty vehicle.

Optionally, the above-mentioned engine auxiliary braking may include exhaust braking, exhaust braking, in-cylinder braking and the like.

Optionally, the aforementioned hydraulic retarder can be replaced by a retarder such as an electric eddy current retarder.

The embodiment of the present invention provides an auxiliary braking control method for heavy-duty vehicles, which can obtain operating parameters related to vehicle braking; compare the operating parameters with the conditions for entering each braking mode, and each braking mode corresponds to at least one The braking device of the car includes: the engine, the motor and the hydraulic retarder; when the operating parameters meet the conditions for entering a braking mode in each braking mode, the braking device corresponding to the braking mode is controlled to assist brake. The embodiment of the present invention judges under what circumstances, and adopts one or more auxiliary braking devices corresponding to the circumstances, so as to achieve the best braking effect. The best braking effect includes the following three aspects:

The present invention not only can recycle the braking energy to the greatest extent, but also can reduce the frequency of use of the service brake on the basis of ensuring the driving safety under the working condition of the long slope.

The invention only requires the driver to operate the auxiliary brake handle once, and does not need to switch gears according to working conditions such as vehicle speed and slope, which reduces driving intensity and improves driving comfort.

The invention fully considers that in the case of emergency braking, the driver does not take any risk-avoiding measures, and takes reasonable and effective braking measures according to the opening of the brake pedal.

Based on the method for controlling the auxiliary braking of a heavy-duty vehicle disclosed in the above-mentioned embodiment of the invention, the embodiment of the present invention also discloses an auxiliary braking control device for a heavy-duty vehicle, as shown in Figure 5, the device includes: an acquisition unit 501, A comparison unit 502 and a control unit 503 .

An acquisition unit 501, configured to acquire operating parameters related to vehicle braking.

It should be noted that the operating parameters include at least one of the opening degree of the brake pedal, the state of the auxiliary brake operating handle, the braking power required by the heavy vehicle, the speed of the heavy vehicle, the ratio of battery power, and the acceleration of the heavy vehicle.

Among them, the brake pedal opening is the brake pedal stepping degree, expressed as a percentage, the higher the brake pedal opening is, the greater the required braking power is;

The state of the auxiliary brake operating handle is divided into open and closed;

The braking power required by the heavy-duty vehicle is calculated according to the formula P=FV=(F1+F2+F3+ma)V, where P is the braking power required by the heavy-duty vehicle, F1 is the frictional resistance between the heavy-duty vehicle and the ground, F2 is the air resistance (wind resistance) of the heavy-duty vehicle, F3 is the slope resistance of the heavy-duty vehicle when driving on the slope, m is the mass of the heavy-duty vehicle, a is the acceleration of the heavy-duty vehicle, and V is the speed of the heavy-duty vehicle;

The battery power ratio is the ratio of the actual remaining power of the car to the total power.

The comparison unit 502 is used to compare the operating parameters with the conditions for entering each braking mode.

It should be noted that each braking mode corresponds to at least one braking device, and the braking device of a car includes: an engine, a motor, and a hydraulic retarder.

The control unit 503 is configured to control the braking device corresponding to the braking mode to perform auxiliary braking when the operating parameters meet the conditions for entering one of the braking modes.

Optionally, in a specific embodiment, the control unit includes: a first control subunit,

The first control subunit is used to control the motor to provide braking power for auxiliary braking when the operating parameters meet the conditions for entering the motor regenerative braking mode;

Wherein, the conditions for entering the regenerative braking mode of the motor include: at least one of the first condition, the second condition, the third condition and the fourth condition,

The first condition is: the state of the auxiliary brake handle is open and the opening of the brake pedal is less than the second opening limit and the braking power required by the heavy-duty vehicle is not greater than the rated power of the motor;

The second condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is less than the third opening limit and the speed of the heavy-duty vehicle is less than the first speed limit;

The third condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is not less than the third opening limit and the braking power required by the heavy-duty vehicle is not greater than the rated power of the motor;

The fourth condition is: the state of the auxiliary brake handle is off, the speed of the heavy vehicle is not less than the first speed limit, and the braking power required by the heavy vehicle is not greater than the rated power of the motor.

Optionally, the control unit also includes: a third control subunit,

The third control subunit is used to control the engine to provide braking power for auxiliary braking when the operating parameters meet the conditions for entering the engine auxiliary braking mode from the motor regenerative braking mode after the heavy-duty vehicle enters the motor regenerative braking mode;

Among them, the conditions for entering the engine auxiliary braking mode from the motor recovery braking mode include: the eighth condition,

The eighth condition is: the battery power ratio is greater than the first power limit.

Optionally, in a specific embodiment, the control unit includes: a second control subunit,

The second control subunit is used to control the engine and the motor to jointly provide braking power for auxiliary braking when the operating parameters meet the conditions for entering the engine-motor combined braking mode;

Wherein, the conditions for entering the engine-motor combined braking mode include: at least one of the fifth condition, the sixth condition and the seventh condition,

The fifth condition is: the state of the auxiliary brake operating handle is open and the opening of the brake pedal is not greater than the second limit value and the braking power required by the heavy-duty vehicle is greater than the rated power of the motor;

The sixth condition is: the state of the auxiliary brake handle is closed and the opening of the brake pedal is not less than the third opening limit and the braking power required by the heavy-duty vehicle is greater than the rated power of the motor;

The seventh condition is: the state of the auxiliary brake handle is off, the speed of the heavy vehicle is not less than the first speed limit, and the braking power required by the heavy vehicle is greater than the rated power of the motor.

Optionally, the control unit also includes: a fourth control subunit,

The fourth control subunit is used for the heavy-duty vehicle to enter the engine-motor combined braking mode for a preset period of time, when the operating parameters meet the requirements for entering the engine-motor-hydraulic retarder combined braking mode from the engine-motor combined braking mode When the conditions are met, the engine, motor and hydraulic retarder are controlled to jointly provide braking power for auxiliary braking;

Among them, the conditions for entering the engine-motor-hydraulic retarder combined braking mode from the engine-motor combined braking mode include: the ninth condition,

The ninth condition is: the acceleration of the heavy vehicle is greater than the first acceleration limit.

Optionally, the control unit also includes: a fifth control subunit,

The fifth control subunit is used to control the engine-motor-hydraulic retarder combined braking mode for a preset period of time when the operating parameters meet the conditions for increasing the opening of the hydraulic retarder solenoid valve. Increase the opening of the solenoid valve of the hydraulic retarder to provide greater braking power for auxiliary braking;

Among them, the conditions for increasing the opening of the solenoid valve of the hydraulic retarder include: the tenth condition,

The tenth condition is: the acceleration of the heavy vehicle is greater than the second acceleration limit.

Optionally, in a specific embodiment, the control unit includes: a sixth control subunit,

The sixth control subunit is used to control the engine and the hydraulic retarder to jointly provide braking power for auxiliary braking when the operating parameters meet the conditions for entering the engine-hydraulic retarder combined braking mode;

Among them, the conditions for entering the engine-hydraulic retarder combined braking mode include: the eleventh condition,

The eleventh condition is: the brake pedal opening is greater than the first opening limit.

Optionally, in a specific embodiment, the control unit includes: a seventh control subunit,

The seventh control subunit is used to control the engine to provide braking power for auxiliary braking when the operating parameters meet the conditions for entering the engine auxiliary braking mode;

Among them, the conditions for entering the engine auxiliary braking mode include: the twelfth condition,

The twelfth condition is: the state of the auxiliary operation brake handle is open and the brake pedal opening is not greater than the first opening limit and the brake pedal opening is greater than the second opening limit, wherein the first opening limit is greater than The second opening limit.

It should be noted that the first opening limit>the second opening limit>the third opening limit, and the first acceleration limit>the second acceleration limit.

An auxiliary braking control device for a heavy-duty vehicle provided in an embodiment of the present invention includes: an acquisition unit 501 , a comparison unit 502 and a control unit 503 . The acquisition unit 501 is used to obtain the operating parameters related to the braking of the vehicle; the comparison unit 502 is used to compare the operating parameters with the conditions for entering each braking mode, and each braking mode corresponds to at least one braking device. The braking device includes: an engine, a motor, and a hydraulic retarder; the control unit 503 is used to control the braking device corresponding to the braking mode to assist when the operating parameters meet the conditions for entering a braking mode in each braking mode. brake. The embodiment of the present invention judges under what circumstances, and adopts one or more auxiliary braking devices corresponding to the circumstances, so as to achieve the best braking effect. The best braking effect includes the following three aspects:

The present invention not only can recycle the braking energy to the greatest extent, but also can reduce the frequency of use of the service brake on the basis of ensuring the driving safety under the working condition of the long slope.

The invention only requires the driver to operate the auxiliary brake handle once, and does not need to switch gears according to working conditions such as vehicle speed and slope, which reduces driving intensity and improves driving comfort.

The invention fully considers that in the case of emergency braking, the driver does not take any risk-avoiding measures, and takes reasonable and effective braking measures according to the opening of the brake pedal.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. An auxiliary brake control method of a heavy-duty vehicle, comprising:

acquiring operation parameters related to automobile braking, wherein the operation parameters comprise at least one of the opening degree of a brake pedal, the state of an auxiliary brake operating handle, the braking power required by the heavy automobile, the speed of the heavy automobile, the battery capacity ratio and the acceleration of the heavy automobile, and the battery capacity ratio is the ratio of the actual residual capacity of the automobile to the total capacity;

comparing the operating parameters with conditions for entering braking modes, each braking mode corresponding to at least one braking device, the braking device of the vehicle comprising: the system comprises an engine, a motor and a hydraulic retarder;

and when the operating parameters meet the condition of entering one of the braking modes, controlling the braking device corresponding to the braking mode to perform auxiliary braking.

2. The method according to claim 1, wherein when the operating parameter satisfies a condition for entering one of the braking modes, controlling a braking device corresponding to the braking mode to perform auxiliary braking comprises:

when the operating parameters meet the condition of entering a motor recovery braking mode, controlling the motor to provide braking power for auxiliary braking;

wherein the condition for entering the motor recovery braking mode comprises: at least one of a first condition, a second condition, a third condition, and a fourth condition,

the first condition is: the auxiliary brake handle is opened, the opening degree of the brake pedal is smaller than a second opening degree limit value, and the brake power required by the heavy-duty car is not larger than the rated power of the motor;

the second condition is: the auxiliary brake handle is closed, the opening degree of the brake pedal is smaller than a third opening limit value, and the speed of the heavy-duty car is smaller than a first speed limit value;

the third condition is: the auxiliary brake handle is closed, the opening degree of the brake pedal is not smaller than the third opening degree limit value, and the brake power required by the heavy-duty car is not larger than the rated power of the motor;

the fourth condition is: the auxiliary brake handle is closed, the speed of the heavy-duty car is not less than the first speed limit value, and the required brake power of the heavy-duty car is not greater than the rated power of the motor.

3. The method according to claim 1, wherein when the operating parameter satisfies a condition for entering one of the braking modes, controlling a braking device corresponding to the braking mode to perform auxiliary braking comprises:

when the operating parameters meet the condition of entering an engine-motor combined braking mode, controlling the engine and the motor to jointly provide braking power for auxiliary braking;

wherein the condition for entering the combined engine-motor braking mode comprises: at least one of a fifth condition, a sixth condition, and a seventh condition,

the fifth condition is: the auxiliary brake operating handle is opened, the opening degree of a brake pedal is not greater than a second limit value, and the required brake power of the heavy truck is greater than the rated power of the motor;

the sixth condition is: the auxiliary brake handle is closed, the opening degree of the brake pedal is not smaller than a third opening degree limit value, and the brake power required by the heavy-duty car is larger than the rated power of the motor;

the seventh condition is: the auxiliary brake handle is closed, the speed of the heavy-duty car is not less than a first speed limit value, and the required brake power of the heavy-duty car is greater than the rated power of the motor.

4. The method according to claim 2, wherein when the operating parameter satisfies a condition for entering one of the braking modes, the method controls a braking device corresponding to the braking mode to perform auxiliary braking, and further comprising:

after the heavy-duty car enters the motor recovery braking mode, when the operation parameters meet the condition that the motor recovery braking mode enters the engine auxiliary braking mode, controlling the engine to provide braking power for auxiliary braking;

wherein the condition for entering the engine auxiliary braking mode from the electric machine recuperation braking mode comprises: in the eighth condition, it is preferable that,

the eighth condition is: the battery capacity ratio is greater than a first capacity limit.

5. The method according to claim 3, wherein when the operating parameter satisfies a condition for entering one of the braking modes, the method controls a braking device corresponding to the braking mode to perform auxiliary braking, and further comprising:

after the heavy-duty car enters the engine-motor combined braking mode for a preset time, when the operation parameters meet the condition of entering the engine-motor-hydraulic retarder combined braking mode from the engine-motor combined braking mode, controlling the engine, the motor and the hydraulic retarder to jointly provide braking power for auxiliary braking;

wherein the condition for entering the combined engine-motor-hydraulic retarder braking mode from the combined engine-motor braking mode comprises the following conditions: in the ninth condition, the first condition is that,

the ninth condition is: the heavy vehicle acceleration is greater than a first acceleration limit.

6. The method of claim 5, wherein when the operating parameter satisfies a condition for entering one of the braking modes, controlling a braking device corresponding to the braking mode to perform auxiliary braking, further comprising:

after the heavy-duty car enters the engine-motor-hydraulic retarder combined braking mode for a preset time, when the operation parameters meet the condition of opening upshift of the hydraulic retarder electromagnetic valve, controlling the opening upshift of the hydraulic retarder electromagnetic valve to provide larger braking power for auxiliary braking;

wherein, the condition that the opening of the electromagnetic valve of the hydraulic retarder shifts up comprises: under the tenth condition, the first condition is that,

the tenth condition is: the acceleration of the heavy-duty vehicle is greater than a second acceleration limit.

7. The method according to claim 1, wherein when the operating parameter satisfies a condition for entering one of the braking modes, controlling a braking device corresponding to the braking mode to perform auxiliary braking comprises:

when the operation parameters meet the condition of entering a combined braking mode of the engine and the hydraulic retarder, controlling the engine and the hydraulic retarder to jointly provide braking power for auxiliary braking;

wherein the condition for entering the combined engine-hydraulic retarder braking mode comprises: under the eleventh condition, the first condition is that,

the eleventh condition is: the brake pedal opening is greater than a first opening limit.

8. The method according to claim 1, wherein when the operating parameter satisfies a condition for entering one of the braking modes, controlling a braking device corresponding to the braking mode to perform auxiliary braking comprises:

when the operating parameters meet the condition of entering an engine auxiliary braking mode, controlling the engine to provide braking power for auxiliary braking;

wherein the condition for entering the engine auxiliary braking mode comprises: in the twelfth condition, it is assumed that,

the twelfth condition is: the auxiliary operation brake handle is opened, the opening degree of the brake pedal is not larger than a first opening degree limiting value, the opening degree of the brake pedal is larger than a second opening degree limiting value, and the first opening degree limiting value is larger than the second opening degree limiting value.

9. An auxiliary brake control apparatus for a heavy vehicle, the apparatus comprising: an acquisition unit, a comparison unit and a control unit,

the acquisition unit is used for acquiring operation parameters related to automobile braking, wherein the operation parameters comprise at least one of the opening degree of a brake pedal, the state of an auxiliary brake operating handle, the braking power required by the heavy automobile, the speed of the heavy automobile, the battery capacity ratio and the acceleration of the heavy automobile, and the battery capacity ratio is the ratio of the actual residual capacity of the automobile to the total capacity;

the comparison unit is used for comparing the operation parameters with conditions for entering various braking modes, each braking mode at least corresponds to one braking device, and the braking device of the automobile comprises: the system comprises an engine, a motor and a hydraulic retarder;

and the control unit is used for controlling a brake device corresponding to the brake mode to perform auxiliary braking when the operation parameter meets the condition of entering one of the brake modes.

10. The apparatus of claim 9,

the control unit includes: a first control sub-unit for controlling the operation of the electronic device,

the first control subunit is used for controlling the motor to provide braking power to perform auxiliary braking when the operation parameters meet the condition of entering a motor recovery braking mode;

wherein the condition for entering the motor recovery braking mode comprises: at least one of a first condition, a second condition, a third condition, and a fourth condition,

the first condition is: the auxiliary brake handle is opened, the opening degree of the brake pedal is smaller than a second opening degree limit value, and the brake power required by the heavy-duty car is not larger than the rated power of the motor;

the second condition is: the auxiliary brake handle is closed, the opening degree of the brake pedal is smaller than a third opening limit value, and the speed of the heavy-duty car is smaller than a first speed limit value;

the third condition is: the auxiliary brake handle is closed, the opening degree of the brake pedal is not smaller than the third opening degree limit value, and the brake power required by the heavy-duty car is not larger than the rated power of the motor;

the fourth condition is: the auxiliary brake handle is closed, the speed of the heavy-duty car is not less than the first speed limit value, and the required brake power of the heavy-duty car is not greater than the rated power of the motor.