CN117627800A - Method and device for eliminating vehicle speed limit point shake and vehicle - Google Patents

Method and device for eliminating vehicle speed limit point shake and vehicle Download PDF

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Publication number
CN117627800A
CN117627800A CN202311691775.3A CN202311691775A CN117627800A CN 117627800 A CN117627800 A CN 117627800A CN 202311691775 A CN202311691775 A CN 202311691775A CN 117627800 A CN117627800 A CN 117627800A
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China
Prior art keywords
vehicle speed
pid control
control strategy
acceleration
actual
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Pending
Application number
CN202311691775.3A
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Chinese (zh)
Inventor
孙翠
向晋波
潘辉
赵东东
王聪
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Dongfeng Huashen Motor Co Ltd
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Dongfeng Huashen Motor Co Ltd
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Priority to CN202311691775.3A priority Critical patent/CN117627800A/en
Publication of CN117627800A publication Critical patent/CN117627800A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D29/00—Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto
    • F02D29/02—Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/04—Introducing corrections for particular operating conditions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/12—Introducing corrections for particular operating conditions for deceleration
    • F02D41/123—Introducing corrections for particular operating conditions for deceleration the fuel injection being cut-off
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/3005—Details not otherwise provided for
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
    • F02D2041/1409—Introducing closed-loop corrections characterised by the control or regulation method using at least a proportional, integral or derivative controller
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/50—Input parameters for engine control said parameters being related to the vehicle or its components
    • F02D2200/501—Vehicle speed
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Controls For Constant Speed Travelling (AREA)

Abstract

The invention discloses a method and a device for eliminating shaking of a vehicle speed limit point and a vehicle, and relates to the technical field of vehicle control; selecting control parameters of a corresponding calibrated PID control strategy, exiting the PID control strategy or stopping oil injection by an oil injector according to the difference between the actual vehicle speed and the target vehicle speed and combining the acceleration of the whole vehicle; and controlling the oil injection quantity of the oil injector according to the selected control parameters of the corresponding calibrated PID control strategy. In a second aspect, the apparatus includes an acquisition module, a determination module, and a control module. In a third aspect, the vehicle comprises the apparatus described above. By the method, the vehicle speed can be controlled more accurately so that the actual vehicle speed of the vehicle is kept near or not exceeding the target vehicle speed, speed limit control is realized, and the vehicle speed limit point shake is controlled completely and effectively.

Description

Method and device for eliminating vehicle speed limit point shake and vehicle
Technical Field
The invention relates to the technical field of vehicle control, in particular to a method and a device for eliminating vehicle speed limit point shake and a vehicle.
Background
In the use process of the vehicle, according to the related legal regulation requirements or actual use requirements, the highest vehicle speed which can be achieved by the vehicle needs to be limited, for example, the highest vehicle speed of a cargo vehicle cannot exceed 90km/h, and the highest vehicle speed of a school bus cannot exceed 80km/h.
The current strategy for limiting the speed of the vehicle is that an engine ECU receives vehicle speed information and judges whether the vehicle speed information is consistent with the set maximum vehicle speed, if the current vehicle speed is smaller than the set maximum vehicle speed, an accelerator is stepped down, the engine starts to spray oil, the engine piston moves to do positive work to increase the engine speed, and the vehicle speed is increased. If the current speed is greater than or equal to the set highest speed, the speed limiting strategy is activated, the ECU rapidly adjusts the fuel injection quantity of the engine to 0, so that the engine stops injecting fuel, and the engine piston is dragged by the vehicle to do negative work to consume the kinetic energy of the vehicle, thereby achieving the purpose of reducing the speed. The accelerator is stepped down during the activation of the speed limiting strategy, and the engine does not spray oil again until the speed of the vehicle is reduced to below 90 km/h.
When the vehicle steps on the full throttle and descends a long slope, the engine immediately stops injecting oil when the vehicle speed exceeds a set speed limit value, and the vehicle speed is quickly reduced below the speed limit value, but because the throttle is stepped on, the engine still responds to the throttle requirement when the vehicle speed is lower than the speed limit value, and at the moment, the vehicle speed is increased to exceed the speed limit value so as to activate the speed limit strategy. Thus, the vehicle is always rapidly fluctuated up and down at the limited speed, and the impact and the shake of the transmission system of the vehicle are caused.
In order to solve the technical problems, a PID control strategy is adopted in the prior art to realize speed limiting control, but the strategy control means only regulates and controls according to the vehicle speed without considering the current acceleration of the vehicle, so that the vehicle speed control is not accurate enough, and the problem of shaking of the speed limiting point of the vehicle cannot be completely and effectively controlled.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a method and a device for eliminating vehicle speed limiting point shake and a vehicle, so as to solve the problem of impact and shake of a transmission system caused by inaccurate vehicle speed limiting strategy control in the prior art.
In order to achieve the above purpose, the invention adopts the following technical scheme:
in a first aspect, the present application provides a method for eliminating vehicle speed limit point shake, including the steps of:
acquiring actual vehicle speed and whole vehicle acceleration;
selecting control parameters of a corresponding calibrated PID control strategy, exiting the PID control strategy or stopping oil injection by the oil injector according to the difference value between the actual vehicle speed and the target vehicle speed and combining the direction of the acceleration of the whole vehicle;
and controlling the oil injection quantity of the oil injector according to the selected control parameters of the corresponding calibrated PID control strategy.
In some optional embodiments, selecting the control parameter of the corresponding calibrated PID control strategy, exiting the PID control strategy, or controlling the fuel injector to stop fuel injection according to the difference between the actual vehicle speed and the target vehicle speed and in combination with the direction of the acceleration of the whole vehicle, includes:
when the actual vehicle speed is greater than the target vehicle speed:
if the difference value between the actual vehicle speed and the target vehicle speed is smaller than the set value, selecting control parameters of a corresponding calibrated PID control strategy according to the acceleration of the whole vehicle;
if the difference value between the actual vehicle speed and the target vehicle speed is larger than the set value, stopping oil injection by the oil injector;
when the actual vehicle speed is smaller than the target vehicle speed:
if the difference value between the actual vehicle speed and the target vehicle speed is smaller than the set value, selecting control parameters of the corresponding calibrated PID control strategy or exiting the PID control strategy according to the whole vehicle acceleration;
if the difference value between the actual vehicle speed and the target vehicle speed is larger than the set value, the PID control strategy is exited.
In some alternative embodiments, if the difference between the actual vehicle speed and the target vehicle speed is smaller than the set value, according to the acceleration of the whole vehicle, selecting the control parameters of the corresponding calibrated PID control strategy, including:
if the acceleration of the whole vehicle is positive, selecting a control parameter of a first calibration PID control strategy;
and if the acceleration of the whole vehicle is a negative value, selecting the control parameter of the second calibration PID control strategy or exiting the PID control strategy.
In some alternative embodiments, the convergence of the control parameters of the first calibrated PID control strategy is greater than the convergence of the control parameters of the second calibrated PID control strategy.
In some alternative embodiments, the set point is 2km/h.
In some alternative embodiments, determining the fuel injection quantity of the fuel injector according to the control parameters of the corresponding calibrated PID control strategy includes:
determining the speed regulation and control quantity of the whole vehicle according to the control parameters of the corresponding calibrated PID control strategy;
determining an engine torque regulating quantity according to the whole vehicle speed regulating quantity;
and determining the oil injection quantity of the oil injector according to the engine torque regulating quantity based on a calibration table of the engine torque and the oil injection quantity of the oil injector.
In some alternative embodiments, the vehicle speed control amount is determined according to the control parameters, including, according toDetermining a vehicle speed regulation quantity u (T), wherein Kp is a proportionality coefficient, T i Is an integral time constant, T d And e (t) is the difference between the actual vehicle speed and the target vehicle speed, and t is the regulation time.
In some alternative embodiments, the interval between two adjacent times of the above-mentioned regulation is 0.1-0.2s.
In a second aspect, the present application further provides a device for eliminating vehicle speed limit point shake, which is configured to implement the method for eliminating vehicle speed limit point shake, and includes:
the acquisition module is used for acquiring the actual vehicle speed and the whole vehicle acceleration;
the judging module is used for selecting control parameters of a corresponding calibrated PID control strategy, exiting the PID control strategy or stopping oil injection by the oil injector according to the difference value between the actual vehicle speed and the target vehicle speed and combining the direction of the acceleration of the whole vehicle;
and the control module is used for controlling the oil injection quantity of the oil injector according to the selected control parameters of the corresponding calibrated PID control strategy.
In a third aspect, the present application further provides a vehicle, including the device for eliminating vehicle speed limit point shake.
Compared with the prior art, the invention has the advantages that:
according to the difference between the actual vehicle speed and the target vehicle speed, and combining the acceleration direction of the whole vehicle, selecting the control parameter of the corresponding calibrated PID control strategy, exiting the PID control strategy or stopping oil injection by the oil injector, and controlling the oil injection quantity of the oil injector according to the selected control parameter of the corresponding calibrated PID control strategy, thereby more accurately controlling the vehicle speed so that the actual vehicle speed of the vehicle is kept near or not exceeding the target vehicle speed, realizing speed limiting control and completely and effectively controlling the shaking of the speed limiting point of the vehicle.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of steps of a method for eliminating vehicle speed limit point shake according to the present invention;
fig. 2 is an engine external characteristic diagram.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of 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 apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.
Embodiments of the present invention are described in further detail below with reference to the accompanying drawings.
In a first aspect, the present application provides a method for eliminating vehicle speed limit point shake, including the steps of:
s1: and acquiring the actual vehicle speed and the acceleration of the whole vehicle.
It will be appreciated that signals from the vehicle speed sensor and various switches may be received by the engine ECU.
S2: and selecting control parameters of a corresponding calibrated PID control strategy, exiting the PID control strategy or stopping oil injection by the oil injector according to the difference between the actual vehicle speed and the target vehicle speed and combining the direction of the acceleration of the whole vehicle.
That is, before the speed limit control is performed, the actual vehicle speed and the target vehicle speed are required to be compared, the degree that the current vehicle speed exceeds the target vehicle speed limit value is judged, and meanwhile, the direction of the current acceleration of the whole vehicle is combined, and the vehicle is judged to be in an acceleration state or a deceleration state, so that the control parameters of the corresponding calibrated PID control strategy are selected or the fuel injector is directly stopped to perform fuel injection, and the speed of the vehicle is controlled.
The combination of the current acceleration direction of the whole vehicle means that the combination of the positive acceleration or the negative deceleration of the acceleration of the whole vehicle, namely that the acceleration is positive and positive acceleration is achieved when the acceleration and the vehicle speed are in the same direction; when the acceleration is opposite to the vehicle speed, the acceleration is negative and the deceleration is negative.
Specifically, the step S2 includes:
when the actual vehicle speed is greater than the target vehicle speed, if the difference between the actual vehicle speed and the target vehicle speed is smaller than a set value, selecting control parameters of a corresponding calibrated PID control strategy according to the acceleration of the whole vehicle; and if the difference value between the actual vehicle speed and the target vehicle speed is larger than the set value, exiting the PID control strategy.
When the actual vehicle speed is smaller than the target vehicle speed, if the difference value between the actual vehicle speed and the target vehicle speed is smaller than a set value, selecting control parameters of a corresponding calibrated PID control strategy or exiting the PID control strategy according to the whole vehicle acceleration; if the difference value between the actual vehicle speed and the target vehicle speed is larger than the set value, the PID control strategy is exited.
For example, when the actual vehicle speed is greater than or less than the target vehicle speed and the difference between the actual vehicle speed and the target vehicle speed is less than the set value, it is indicated that the actual vehicle speed is near the target vehicle speed at this time, so that the control parameters of the corresponding calibrated PID control strategy can be selected according to the acceleration of the whole vehicle, so that the ECU can regulate and control the fuel injection amount each time in a small manner, thereby controlling the rotational speed of the engine in a small manner, and keeping the actual vehicle speed near the target vehicle speed.
When the actual vehicle speed is greater than the target vehicle speed and the difference between the actual vehicle speed and the target vehicle speed is greater than the set value, the actual vehicle speed exceeds the upper limit section of the target vehicle speed, so that the fuel injector immediately stops fuel injection, and the engine stops doing positive work.
When the actual vehicle speed is smaller than the target vehicle speed and the difference between the actual vehicle speed and the target vehicle speed is larger than the set value, the actual vehicle speed is not up to the target vehicle speed at the moment, so that the PID control strategy can be exited, and the ECU responds according to the requirement of the accelerator of the driver.
When the actual vehicle speed is smaller than the target vehicle speed and the acceleration of the whole vehicle is positive, the vehicle speed is changed by regulating and controlling the fuel injection quantity through the control parameter of the first calibration PID control strategy, and if the regulation and control is over-regulated to enable the actual vehicle speed to be larger than the target vehicle speed and the difference value between the actual vehicle speed and the target vehicle speed to be larger than a set value, the direct fuel injector stops fuel injection.
In some optional embodiments, when the actual vehicle speed is greater than or less than the target vehicle speed and the difference between the actual vehicle speed and the target vehicle speed is less than the set value, if the acceleration of the whole vehicle is a positive value, selecting a control parameter of the first calibration PID control strategy; when the actual vehicle speed is greater than or less than the target vehicle speed and the difference between the actual vehicle speed and the target vehicle speed is less than the set value, if the acceleration of the whole vehicle is a negative value, selecting the control parameter of a second calibration PID control strategy.
It can be understood that when the acceleration is positive, it indicates that the vehicle has a tendency to continue accelerating at this time, and because the difference between the actual vehicle speed and the target vehicle speed is smaller than the set value, the actual vehicle speed is near the target vehicle speed, so that under the control of the control parameter of the first calibration PID control strategy, the ECU can increase the engine speed by a smaller magnitude every time the fuel injection amount is regulated, and the vehicle speed of the whole vehicle approaches the target vehicle speed by a smaller magnitude. When the acceleration is negative, the trend of deceleration of the vehicle is indicated, at the moment, under the regulation and control of the control parameters of the first calibration PID control strategy, the ECU can reduce the engine rotation speed by a small margin every time the fuel injection quantity is regulated and controlled, so that the vehicle speed is slowly reduced to be near the target vehicle speed, and the vehicle is enabled to reach near the target vehicle speed faster on the premise of ensuring the running stability of the vehicle, and the system is prevented from vibrating.
It should be noted that, the first calibration PID control strategy and the second calibration PID control strategy may set PID control parameters according to each engine condition, and may establish a correspondence between an engine condition and the PID control parameters, where the correspondence includes multiple preset engine conditions and PID control parameters corresponding to each preset engine condition.
In some alternative embodiments, the convergence of the control parameters of the first calibrated PID control strategy is greater than the convergence of the control parameters of the second calibrated PID control strategy.
The aim of the arrangement is that, because the control parameter of the first calibration PID control strategy is selected when the acceleration is positive, and the second calibration PID control strategy is selected when the acceleration is negative, the vehicle can reach or keep near the target vehicle speed more quickly under the control of the control parameter of the first calibration PID control strategy and the acceleration trend, and the vehicle can reach near the target vehicle speed more quickly under the control of the control parameter of the second calibration PID control strategy.
In some alternative embodiments, the set point is 2km/h.
For example, the difference between the actual vehicle speed u1 and the target vehicle speed u2 is defined as e, i.e., e=u1-u 2.
When e is more than or equal to 2km/h, representing that the actual vehicle speed is far greater than the target vehicle speed, the ECU judges that the vehicle speed can continuously increase according to the acceleration (positive value) of the whole vehicle, at the moment, the ECU controls the fuel injector to stop fuel injection immediately, the engine stops doing positive work, and the engine is dragged backward on a downhill road to begin doing negative work to consume the kinetic energy of the whole vehicle.
When e is more than or equal to 0km/h and less than 2km/h, the actual vehicle speed is near the target vehicle speed and is larger than the target vehicle speed. If the acceleration of the whole vehicle is positive, which represents that the whole vehicle has a continuous acceleration trend, the control parameter of a first calibration PID control strategy is selected, and the ECU can increase the engine speed by a small margin every time the fuel injection quantity is regulated and controlled, and the engine speed is kept in the interval range of 0km/h less than or equal to e less than 2km/h. If overshoot occurs so that e is more than or equal to 2km/h, the ECU controls the fuel injector to stop fuel injection immediately. If the acceleration of the whole vehicle is negative, representing that the whole vehicle is decelerating, selecting a control parameter of a second calibration PID control strategy, enabling the rotation speed of the engine to be reduced slightly by the ECU when the ECU regulates and controls the oil injection quantity once, and enabling the vehicle speed to be reduced slowly to be near the target vehicle speed.
When the speed e is less than or equal to-2 km/h and less than 0km/h, the actual speed is near the target speed, and the actual speed is lower than the target speed. If the acceleration of the whole vehicle is positive, the acceleration of the whole vehicle is represented to have a continuous acceleration trend. The control parameters of the first calibration PID control strategy are selected, and the ECU can enable the rotation speed of the engine to be increased slightly after regulating and controlling the oil injection quantity once, so that the speed of the whole vehicle approaches to the target speed slightly. If the acceleration of the whole vehicle is a negative value, the whole vehicle has a deceleration trend, and the regulation is not performed at the moment, and the PID control strategy is exited.
When e < -2km/h, representing that the actual vehicle speed is far lower than the target vehicle speed, the system exits the PID control strategy, and the ECU responds according to the requirement of the accelerator of the driver.
S3: and controlling the oil injection quantity of the oil injector according to the control parameters of the corresponding calibrated PID control strategy.
In some alternative embodiments, the step S3 includes:
s31: and determining the speed regulation and control quantity of the whole vehicle according to the control parameters of the corresponding calibrated PID control strategy.
In some alternative embodiments, the vehicle speed control amount is determined according to the control parameters, including, according toDetermining a vehicle speed regulation quantity u (T) of the whole vehicle, wherein Kp is a proportionality coefficient and T i Is an integral time constant, T d And e (t) is the difference between the actual vehicle speed and the target vehicle speed, and t is the regulation time.
It will be appreciated that the calculated control amounts are different under different engine operating conditions, even if the same difference, due to the different control parameters of the PID control strategy.
And the control parameters of the PID control strategy comprise Kp and T i 、T d . Specific Kp, T i 、T d The PID control parameters can be set according to each engine working condition, and a corresponding relation between the engine working condition and the PID control parameters can be established, wherein the corresponding relation comprises a plurality of preset engine working conditions and the PID control parameters corresponding to each preset engine working condition.
In some alternative embodiments, the adjustment time intervals are between 0.1 and 0.2 seconds. The aim of this arrangement is to avoid frequent adjustment of the fuel injection quantity of the engine and acceleration and deceleration changes of the vehicle speed, taking into account comfort and fuel economy.
S32: and determining the current engine torque regulating quantity according to the whole vehicle speed regulating quantity.
It will be appreciated that since the engine speed may be based on u=0.377 rn/(i) g i 0 ) Determining, wherein u is the vehicle speed, r is the tire rolling radius, n is the current engine speed, i g I is the current gearbox speed ratio 0 Is the rear axle speed ratio.
After the engine speed is determined, the torque of the engine at the current speed can be obtained according to the external characteristic diagram of the engine.
For example, as shown in FIG. 2, the torque of the engine at the current rotational speed may be determined.
S33: and determining the oil injection quantity of the oil injector according to the engine torque control quantity based on the engine torque and the oil injection quantity calibration table of the oil injector.
In a second aspect, the present application further provides a device for eliminating vehicle speed limit point shake, which is configured to implement the method for eliminating vehicle speed limit point shake, and includes an acquisition module, a judgment module, and a control module.
Specifically, the acquisition module is used for acquiring the actual vehicle speed and the whole vehicle acceleration; the judging module is used for selecting control parameters of a corresponding calibrated PID control strategy, exiting the PID control strategy or stopping oil injection by the oil injector according to the difference value between the actual vehicle speed and the target vehicle speed and combining the direction of the acceleration of the whole vehicle; and the control module controls the oil injection quantity of the oil injector according to the selected control parameters of the corresponding calibrated PID control strategy.
It is understood that the acquisition module receives signals from the vehicle speed sensor and various switches via the engine ECU.
After the actual vehicle speed and the whole vehicle acceleration are obtained, the actual vehicle speed and the target vehicle speed are required to be compared before the speed limiting control is carried out, the degree that the current vehicle speed exceeds the target vehicle speed limit value is judged, meanwhile, the direction of the current acceleration of the whole vehicle is combined, the vehicle is judged to be in an accelerating state or a decelerating state, and then the control module selects the control parameters of the corresponding calibrated PID control strategy or directly enables the fuel injector to stop fuel injection so as to control the speed of the vehicle.
Specifically, when the actual vehicle speed is greater than the target vehicle speed, if the difference between the actual vehicle speed and the target vehicle speed is smaller than a set value, selecting control parameters of a corresponding calibrated PID control strategy according to the acceleration of the whole vehicle; and if the difference value between the actual vehicle speed and the target vehicle speed is larger than the set value, exiting the PID control strategy.
When the actual vehicle speed is smaller than the target vehicle speed, if the difference value between the actual vehicle speed and the target vehicle speed is smaller than a set value, selecting control parameters of a corresponding calibrated PID control strategy or exiting the PID control strategy according to the whole vehicle acceleration; if the difference value between the actual vehicle speed and the target vehicle speed is larger than the set value, the PID control strategy is exited.
For example, when the actual vehicle speed is greater than or less than the target vehicle speed and the difference between the actual vehicle speed and the target vehicle speed is less than the set value, it is indicated that the actual vehicle speed is near the target vehicle speed at this time, so that the control parameters of the corresponding calibrated PID control strategy can be selected according to the acceleration of the whole vehicle, so that the ECU can regulate and control the fuel injection amount each time in a small manner, thereby controlling the rotational speed of the engine in a small manner, and keeping the actual vehicle speed near the target vehicle speed.
When the actual vehicle speed is greater than the target vehicle speed and the difference between the actual vehicle speed and the target vehicle speed is greater than the set value, the actual vehicle speed exceeds the upper limit section of the target vehicle speed, so that the fuel injector immediately stops fuel injection, and the engine stops doing positive work.
When the actual vehicle speed is smaller than the target vehicle speed and the difference between the actual vehicle speed and the target vehicle speed is larger than the set value, the actual vehicle speed is not up to the target vehicle speed at the moment, so that the PID control strategy can be exited, and the ECU responds according to the requirement of the accelerator of the driver.
When the actual vehicle speed is smaller than the target vehicle speed and the acceleration of the whole vehicle is positive, the vehicle speed is changed by regulating and controlling the fuel injection quantity through the control parameter of the first calibration PID control strategy, and if the regulation and control is over-regulated to enable the actual vehicle speed to be larger than the target vehicle speed and the difference value between the actual vehicle speed and the target vehicle speed to be larger than a set value, the direct fuel injector stops fuel injection.
In some optional embodiments, when the actual vehicle speed is greater than or less than the target vehicle speed and the difference between the actual vehicle speed and the target vehicle speed is less than the set value, if the acceleration of the whole vehicle is a positive value, selecting a control parameter of the first calibration PID control strategy; when the actual vehicle speed is greater than or less than the target vehicle speed and the difference between the actual vehicle speed and the target vehicle speed is less than the set value, if the acceleration of the whole vehicle is a negative value, selecting the control parameter of a second calibration PID control strategy.
It can be understood that when the acceleration is positive, it indicates that the vehicle has a tendency to continue accelerating at this time, and because the difference between the actual vehicle speed and the target vehicle speed is smaller than the set value, the actual vehicle speed is near the target vehicle speed, so that under the control of the control parameter of the first calibration PID control strategy, the ECU can increase the engine speed by a smaller magnitude every time the fuel injection amount is regulated, and the vehicle speed of the whole vehicle approaches the target vehicle speed by a smaller magnitude. When the acceleration is negative, the trend of deceleration of the vehicle is indicated, at the moment, under the regulation and control of the control parameters of the first calibration PID control strategy, the ECU can reduce the engine rotation speed by a small margin every time the fuel injection quantity is regulated and controlled, so that the vehicle speed is slowly reduced to be near the target vehicle speed, and the vehicle is enabled to reach near the target vehicle speed faster on the premise of ensuring the running stability of the vehicle, and the system is prevented from vibrating.
Therefore, according to different directions of acceleration, corresponding control intervals are divided to select control parameters of corresponding calibration PID control strategies, and control accuracy of the PID control strategies is further improved.
It should be noted that, the first calibration PID control strategy and the second calibration PID control strategy may set PID control parameters according to each engine condition, and may establish a correspondence between an engine condition and the PID control parameters, where the correspondence includes multiple preset engine conditions and PID control parameters corresponding to each preset engine condition.
In some alternative embodiments, the convergence of the control parameters of the first calibrated PID control strategy is greater than the convergence of the control parameters of the second calibrated PID control strategy.
The aim of the arrangement is that, because the control parameter of the first calibration PID control strategy is selected when the acceleration is positive, and the second calibration PID control strategy is selected when the acceleration is negative, the vehicle can reach or keep near the target vehicle speed more quickly under the control of the control parameter of the first calibration PID control strategy and the acceleration trend, and the vehicle can reach near the target vehicle speed more quickly under the control of the control parameter of the second calibration PID control strategy.
In some alternative embodiments, the set point is 2km/h.
For example, the difference between the actual vehicle speed u1 and the target vehicle speed u2 is defined as e, i.e., e=u1-u 2.
When e is more than or equal to 2km/h, representing that the actual vehicle speed is far greater than the target vehicle speed, the ECU judges that the vehicle speed can continuously increase according to the acceleration (positive value) of the whole vehicle, at the moment, the ECU controls the fuel injector to stop fuel injection immediately, the engine stops doing positive work, and the engine is dragged backward on a downhill road to begin doing negative work to consume the kinetic energy of the whole vehicle.
When e is more than or equal to 0km/h and less than 2km/h, the actual vehicle speed is near the target vehicle speed and is larger than the target vehicle speed. If the acceleration of the whole vehicle is positive, which represents that the whole vehicle has a continuous acceleration trend, the judging module selects the control parameter of the first calibration PID control strategy, and the ECU can increase the engine speed by a small margin every time the fuel injection quantity is regulated and controlled, and the engine speed is kept in the interval range of 0km/h less than or equal to e less than 2km/h. If overshoot occurs so that e is more than or equal to 2km/h, the ECU controls the fuel injector to stop fuel injection immediately. If the acceleration of the whole vehicle is negative, representing that the whole vehicle is decelerating, the judging module selects the control parameter of the second calibration PID control strategy, and the ECU can reduce the rotating speed of the engine to a small extent every time the fuel injection quantity is regulated and controlled, so that the vehicle speed is slowly reduced to be near the target vehicle speed.
When the speed e is less than or equal to-2 km/h and less than 0km/h, the actual speed is near the target speed, and the actual speed is lower than the target speed. If the acceleration of the whole vehicle is positive, the acceleration of the whole vehicle is represented to have a continuous acceleration trend. The judging module selects the control parameter of the first calibration PID control strategy, and the ECU can enable the rotation speed of the engine to be increased slightly when the ECU regulates and controls the oil injection quantity once, so that the speed of the whole automobile approaches to the target speed slightly. If the acceleration of the whole vehicle is a negative value, the speed of the whole vehicle is reduced, and the speed is not regulated at the moment, and the judging module exits from the PID control strategy.
When e < -2km/h, representing that the actual vehicle speed is far lower than the target vehicle speed, the judging module exits the PID control strategy, and the ECU responds according to the requirement of the accelerator of the driver.
After the judging module selects the control parameters of the corresponding calibrated PID control strategy, the control module determines the speed regulation and control quantity of the whole vehicle according to the control parameters of the corresponding calibrated PID control strategy.
Specifically, the control parameter of the corresponding calibrated PID control strategy is used for determining the speed regulation quantity of the whole vehicle, determining the current engine torque according to the speed regulation quantity of the whole vehicle, determining the fuel injection quantity of the fuel injector according to the engine torque based on a calibration table of the engine torque and the fuel injection quantity of the fuel injector.
In some alternative embodiments, the vehicle speed control amount is determined according to the control parameters, including, according toDetermining a vehicle speed regulation quantity u (T) of the whole vehicle, wherein Kp is a proportionality coefficient and T i Is an integral time constant, T d And e (t) is the difference between the actual vehicle speed and the target vehicle speed, and t is the regulation time.
It will be appreciated that the calculated control amounts are different under different engine operating conditions, even if the same difference, due to the different control parameters of the PID control strategy.
And the control parameters of the PID control strategy comprise Kp and T i 、T d . Specific Kp, T i 、T d The PID control parameters can be set according to each engine working condition, and a corresponding relation between the engine working condition and the PID control parameters can be established, wherein the corresponding relation comprises a plurality of preset engine working conditions and the PID control parameters corresponding to each preset engine working condition.
In some alternative embodiments, the adjustment time intervals are between 0.1 and 0.2 seconds. The aim of this arrangement is to avoid frequent adjustment of the fuel injection quantity of the engine and acceleration and deceleration changes of the vehicle speed, taking into account comfort and fuel economy.
It will be appreciated that since the engine speed may be based on u=0.377 rn/(i) g i 0 ) Determining, wherein u is the vehicle speed, r is the tire rolling radius, n is the current engine speed, i g I is the current gearbox speed ratio 0 Is the rear axle speed ratio.
After the engine speed is determined, the torque of the engine at the current speed can be obtained according to the external characteristic diagram of the engine.
And determining the oil injection quantity of the oil injector according to the engine torque control quantity based on the engine torque and the oil injection quantity calibration table of the oil injector.
In a third aspect, the present application further provides a vehicle, including the device for eliminating vehicle speed limit point shake.
According to the method, the device and the vehicle for eliminating the shaking of the vehicle speed limit point, the control parameters of the corresponding calibrated PID control strategy are selected, the PID control strategy is exited or the fuel injector stops injecting fuel according to the difference between the actual vehicle speed and the target vehicle speed and the direction of the acceleration of the whole vehicle, and the fuel injection quantity of the fuel injector is controlled according to the selected control parameters of the corresponding calibrated PID control strategy, so that the vehicle speed can be controlled more accurately, the actual vehicle speed of the vehicle is kept near or not exceeding the target vehicle speed, the speed limit control is realized, and the shaking of the vehicle speed limit point is completely and effectively controlled.
In the description of the present application, it should be noted that the azimuth or positional relationship indicated by the terms "upper", "lower", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of description of the present application and simplification of the description, and are not indicative or implying that the apparatus or element in question must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present application. Unless specifically stated or limited otherwise, the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.
It should be noted that in this 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. Moreover, 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 phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing is merely a specific embodiment of the application to enable one skilled in the art to understand or practice the 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 (10)

1. A method of eliminating vehicle speed limit point shake, comprising the steps of:
acquiring actual vehicle speed and whole vehicle acceleration;
selecting control parameters of a corresponding calibrated PID control strategy, exiting the PID control strategy or stopping oil injection by the oil injector according to the difference value between the actual vehicle speed and the target vehicle speed and combining the direction of the acceleration of the whole vehicle;
and controlling the oil injection quantity of the oil injector according to the selected control parameters of the corresponding calibrated PID control strategy.
2. The method for eliminating vehicle speed limit point shake according to claim 1, wherein selecting control parameters of a corresponding calibrated PID control strategy, exiting the PID control strategy or controlling a fuel injector to stop fuel injection according to a difference between an actual vehicle speed and a target vehicle speed and in combination with a direction of acceleration of the whole vehicle comprises:
when the actual vehicle speed is greater than the target vehicle speed:
if the difference value between the actual vehicle speed and the target vehicle speed is smaller than the set value, selecting control parameters of a corresponding calibrated PID control strategy according to the acceleration of the whole vehicle;
if the difference value between the actual vehicle speed and the target vehicle speed is larger than the set value, stopping oil injection by the oil injector;
when the actual vehicle speed is smaller than the target vehicle speed:
if the difference value between the actual vehicle speed and the target vehicle speed is smaller than the set value, selecting control parameters of the corresponding calibrated PID control strategy or exiting the PID control strategy according to the whole vehicle acceleration;
if the difference value between the actual vehicle speed and the target vehicle speed is larger than the set value, the PID control strategy is exited.
3. The method for eliminating vehicle speed limit point shake according to claim 1, wherein selecting control parameters of the corresponding calibrated PID control strategy according to the vehicle acceleration if the difference between the actual vehicle speed and the target vehicle speed is smaller than the set value comprises:
if the acceleration of the whole vehicle is positive, selecting a control parameter of a first calibration PID control strategy;
and if the acceleration of the whole vehicle is a negative value, selecting the control parameter of the second calibration PID control strategy or exiting the PID control strategy.
4. A method of eliminating vehicle speed limit point shake as defined in claim 3 wherein the convergence magnitude of the control parameter of said first calibrated PID control strategy is greater than the convergence magnitude of the control parameter of said second calibrated PID control strategy.
5. The method of eliminating vehicle speed limit point shake according to claim 2, wherein the set value is 2km/h.
6. The method of eliminating vehicle speed limit point shake according to claim 1, wherein determining the fuel injection amount of the fuel injector according to the control parameter of the corresponding calibrated PID control strategy comprises:
determining the speed regulation and control quantity of the whole vehicle according to the control parameters of the corresponding calibrated PID control strategy;
determining an engine torque regulating quantity according to the whole vehicle speed regulating quantity;
and determining the oil injection quantity of the oil injector according to the engine torque regulating quantity based on a calibration table of the engine torque and the oil injection quantity of the oil injector.
7. The method of eliminating vehicle speed limit point shake according to claim 6, wherein determining the vehicle speed regulation amount based on the control parameter comprises, based on Determining a vehicle speed regulation quantity u (T), wherein Kp is a proportionality coefficient, T i Is an integral time constant, T d And e (t) is the difference between the actual vehicle speed and the target vehicle speed, and t is the regulation time.
8. The method of eliminating vehicle speed limit point shake according to claim 7, wherein the interval between two adjacent times of the regulation time is 0.1-0.2s.
9. An apparatus for eliminating vehicle speed limit point shake, characterized by implementing a method for eliminating vehicle speed limit point shake according to any one of claims 1 to 8, comprising:
the acquisition module is used for acquiring the actual vehicle speed and the whole vehicle acceleration;
the judging module is used for selecting control parameters of a corresponding calibrated PID control strategy, exiting the PID control strategy or stopping oil injection by the oil injector according to the difference value between the actual vehicle speed and the target vehicle speed and combining the direction of the acceleration of the whole vehicle;
and the control module is used for controlling the oil injection quantity of the oil injector according to the selected control parameters of the corresponding calibrated PID control strategy.
10. A vehicle comprising the apparatus for eliminating vehicle speed limit point shake according to claim 9.
CN202311691775.3A 2023-12-11 2023-12-11 Method and device for eliminating vehicle speed limit point shake and vehicle Pending CN117627800A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311691775.3A CN117627800A (en) 2023-12-11 2023-12-11 Method and device for eliminating vehicle speed limit point shake and vehicle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311691775.3A CN117627800A (en) 2023-12-11 2023-12-11 Method and device for eliminating vehicle speed limit point shake and vehicle

Publications (1)

Publication Number Publication Date
CN117627800A true CN117627800A (en) 2024-03-01

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202311691775.3A Pending CN117627800A (en) 2023-12-11 2023-12-11 Method and device for eliminating vehicle speed limit point shake and vehicle

Country Status (1)

Country Link
CN (1) CN117627800A (en)

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