CN113264045B

CN113264045B - Self-adaptive cruise energy management method and controller for plug-in hybrid electric vehicle

Info

Publication number: CN113264045B
Application number: CN202110655388.9A
Authority: CN
Inventors: 潘公宇; 郭丛摇
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2021-06-11
Filing date: 2021-06-11
Publication date: 2022-10-28
Anticipated expiration: 2041-06-11
Also published as: CN113264045A

Abstract

The invention discloses a self-adaptive cruise energy management method and a controller for a plug-in hybrid electric vehicle, and mainly relates to a self-adaptive cruise energy management strategy for the plug-in hybrid electric vehicle, which is provided with a self-adaptive cruise mode control layer with upper multi-mode identification and switching, a middle energy management method matching control layer and a lower torque distribution control layer, designs the corresponding self-adaptive cruise control strategy according to different working conditions and road conditions, and generates corresponding expected acceleration; the PHEV is added with the charging function of an external power grid on the basis of the HEV, can run for a long distance in a pure electric mode, and can also be in a hybrid power mode when required; according to the cruise control strategy and the expected acceleration, the corresponding energy management strategy of the plug-in hybrid electric vehicle is matched, so that the battery electric quantity is fully consumed in one trip or before the next charging, the engine works in an efficient working interval, the energy is utilized to the maximum, and the fuel consumption is reduced.

Description

Self-adaptive cruise energy management method and controller for plug-in hybrid electric vehicle

Technical Field

The invention belongs to the technical field of intelligent auxiliary driving and energy management of automobiles, and particularly relates to a self-adaptive cruise energy management method and a controller based on a plug-in hybrid electric vehicle under the condition of considering road gradient, curve and sliding.

Background

At present, the problems of energy shortage and environmental pollution are increasingly highlighted, and the development of new energy automobiles becomes one of ideal ways for relieving energy and environmental crisis. The Plug-in Hybrid Electric Vehicle (PHEV) has environmental protection of a pure Electric Vehicle (EV) and practicality of a traditional Hybrid Electric Vehicle (HEV), on one hand, driving range can be increased, the requirement of long-distance driving is met, on the other hand, zero emission of short-distance driving can be achieved, electric energy is used more, and the Plug-in Hybrid Electric Vehicle (PHEV) becomes a new energy Vehicle with the best development prospect at present. The PHEV energy management strategy is one of key technologies for realizing low fuel consumption and low emission of vehicles as a core part. Therefore, how to make an effective and practical energy management strategy is a very research-worthy problem.

In addition, the adaptive cruise control system is an important component of an intelligent driving system, is an upgrade of a traditional constant-speed cruise control system, can enable a vehicle to keep the speed set by a driver, can also enable the vehicle and a front vehicle to keep the time distance set by the driver to follow a target of the front vehicle for driving, and can adaptively carry out acceleration and deceleration control.

In order to comprehensively solve the problems of safety, energy conservation and environmental protection of vehicles from the aspect of vehicle system control, break through the limitation that related technical researches are still independently carried out in the field of new energy vehicles and the field of intelligent vehicles at present, a plug-in hybrid electric vehicle self-adaptive cruise energy management strategy which integrates the advanced technologies of new energy vehicles and intelligent vehicles, including cruise mode switching, vehicle energy management mode identification and torque distribution control, is provided.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the defects in the prior art, the invention provides a plug-in hybrid electric vehicle adaptive cruise energy management method, which integrates new energy and respective advanced technologies of intelligent vehicles to generate a set of cruise modes matched with different working conditions, can be matched with an appropriate energy management method according to specific conditions, fully exerts the advantages of two power sources under the condition of ensuring the normal running of the vehicle so as to realize complementation, and mainly relates to the plug-in hybrid electric vehicle adaptive cruise energy management method which is provided with an upper-layer multi-mode recognition and switching adaptive cruise mode control layer, a middle-layer energy management method matching control layer and a lower-layer torque distribution control layer.

A self-adaptive cruise energy management method for a plug-in hybrid electric vehicle comprises the following steps:

step one, collecting road traffic information: the real-time collection of the road traffic information of the vehicle comprises the following steps: slope, camber, with the distance of preceding car, preceding car speed, whether have traffic signal lamp and state in certain distance to and the running state information of car certainly, include: the vehicle speed and the vehicle SOC.

Step two, designing a self-adaptive cruise energy hierarchical management strategy of the plug-in hybrid electric vehicle: the adaptive cruise energy hierarchical manager mainly comprises an upper-layer multi-mode recognition and switching adaptive cruise mode control layer, a middle-layer energy management method matching control layer and a lower-layer torque distribution control layer. The upper-layer multi-mode recognition and switching adaptive cruise mode control layer judges a cruise mode which a vehicle needs to be matched with and outputs expected acceleration under the current mode according to collected road traffic information, the middle-layer energy management method matching control layer preferentially distributes working modes of an engine and a motor under special road conditions according to the specific cruise mode matched with the upper-layer multi-mode recognition and switching adaptive cruise mode control layer and the distance from a destination, the lower-layer torque distribution control layer calculates required torque according to the expected acceleration output by the upper-layer multi-mode recognition and switching adaptive cruise mode control layer and judges whether the working modes of the engine and the motor preferentially distributed by the middle-layer energy management method matching control layer are reasonable according to a set rule, if not, other working modes are distributed, and the control layer can distribute the torques of the engine and the motor for all working conditions in the driving process.

Further, the second step includes the following processes in the adaptive cruise control layer for upper multi-mode identification and switching:

firstly, judging whether the road condition belongs to a complex road condition mode or not according to input curvature and gradient information, then judging whether a sliding cruise mode, a constant speed cruise mode or a following cruise mode is matched according to the input speed of a front vehicle, the speed of the front vehicle, the distance between the front vehicle and a certain distance and the state of a traffic signal lamp, and finally determining that the complex road condition sliding cruise mode, the non-complex road condition sliding cruise mode, the complex road condition constant speed cruise mode, the non-miscellaneous road condition constant speed cruise mode, the complex road condition following cruise mode or the non-complex road condition following cruise mode is required to be entered under the condition according to the input information.

Defining that when the curvature K is zero, the road does not belong to a curve, and when the gradient theta is zero, the road without the gradient is a level road, so that under the condition that the curvature K is 0 and the gradient theta is also 0, the road condition is a non-complex road condition mode, otherwise, the road condition is a complex road condition mode;

defining L to represent whether a traffic signal lamp exists in a distance and a representation value of the state of the traffic signal lamp, when the L is 1, the traffic signal lamp exists in the road section and the road section is a red light, at the moment, the vehicle should enter a sliding cruise mode, in the mode, the vehicle adjusts the vehicle speed to V1 within the newly expected acceleration generated by the vehicle in the X1 distance, and the speed can be ensured to be within the distance s _f The internal neutral coasting relies on rolling resistance and air resistance to reduce the vehicle speed to just zero speed at the traffic light, wherein the general kinematic formula is

C _rr Is the rolling resistance coefficient; theta is the road grade; ρ is the air density; a is the windward area, namely the projection area of the driving direction of the automobile; m is the mass of the whole vehicle; f _w Is a driving force; c _D Is the air resistance coefficient; v represents the instantaneous speed at each moment during the driving;

during taxi cruise, at t _s Distance s traveled in time _f Energy calculation equation E involved _w Comprises the following steps:

s _f a neutral glide distance; t is t _s Elapsed time for neutral coast; e _w Energy consumed in the sliding process; v is the instantaneous speed at each moment under the influence of the deceleration generated by rolling resistance and air resistance during neutral coasting;

speed V when entering sliding mode ₁ Is composed of

Wherein s is _f A neutral glide distance; a is _f Deceleration due to rolling resistance and air resistance;

when the speed of the vehicle is V and the distance between the vehicle and the signal lamp is S when the traffic signal lamp is red, X ₁ Is composed of

X ₁ ＝S-s _f

When L is 0 or-1, the road section is respectively represented to have no traffic signal lamp or the traffic signal lamp is green, and the vehicle enters other cruising modes;

defining a distance error Δ d = d-d _des Wherein d is the distance between the vehicle and the front vehicle at the moment, and delta d is the distance error; d _des To a desired vehicle distance, d _des Can be expressed as d _des ＝τ _h v+d ₀ Wherein tau is _h Time interval of the head of a vehicle, d ₀ V is the instantaneous speed of the vehicle in the process of driving at the minimum safe distance; defining the maximum distance d from the front vehicle _set Wherein d is _set ＝d _des + Δ x, wherein Δ x =1.5 × d _des ；

When d > d is satisfied _set ||d＜d _des The following vehicle cruise mode is entered, if d is larger than d _set Indicating that a distance from the front vehicle is far, a new expected acceleration adjustment and a distance d from the front vehicle should be generated _des If d is less than d _des It indicates that the distance to the front vehicle is closer and the new expected acceleration adjustment and the distance to the front vehicle d should be generated _des The speed is simultaneously adjusted to V _set ；

When d is satisfied _des ≤d≤d _set The method comprises entering a constant-speed cruise mode in which the control target of the speed of the vehicle is the cruise speed V set by the driver _set In which V is _set The specific values are:

r is the wheel radius; n is the rotation of the engine working in the high-efficiency regionSpeed; i.e. i _g Is the transmission ratio of the transmission; i.e. i ₀ The transmission ratio of the main speed reducer is set;

the step two, the matching of the middle layer energy management method and the control layer comprises the following processes:

the vehicle obtains the travel distance before starting, and if the travel distance D is less than the pure electric endurance mileage D of the vehicle _m And the whole travel enters a pure electric mode, the purposes of zero emission and zero oil consumption are realized, the SOC value of the battery reaches a preset lower limit value when the travel is finished, and the electric energy is supplemented by utilizing the advantages that the capacity of a power battery pack of the plug-in hybrid electric vehicle is large and the power battery pack can be charged by an external power grid, so that the energy utilization rate is highest. If the travel distance is greater than the pure electric cruising range of the vehicle or the travel distance is unclear, judging the value of M according to an adaptive cruise mode control layer which is identified and switched by an upper layer of multi-modes, wherein the value of M is defined as a sliding cruise mode when the value of M is 1, a following cruise mode when the value of M is 2, and a constant cruise mode when the value of M is 3;

when the vehicle is in the sliding cruise mode, the pure electric mode is preferentially selected on the premise that the vehicle speed is lower and the vehicle is frequently accelerated and decelerated in a congested road section in a city road at the moment, the vehicle is driven by the motor to run under a low-load working condition, and the engine is prevented from working in a low-efficiency area with low speed and low torque;

when the vehicle is in a constant-speed cruising mode, the vehicle mostly runs at a medium-high speed, and the vehicle is positioned on suburban roads or high-speed road sections, so that the charging mode is preferentially selected on the premise of meeting torque and SOC (state of charge), the set cruising speed ensures that the engine works in a high-efficiency area, and the surplus power is utilized to charge the power battery pack while the power required by driving the vehicle is provided;

when the following cruise mode is adopted, the vehicle needs to be accelerated and decelerated frequently according to the distance from the front vehicle, and the vehicle speed is low, so that the vehicle works in a low-speed low-load working condition, a pure electric mode is preferentially selected on the premise of meeting the torque and the SOC, the motor is used for driving the vehicle to run independently, and the engine is prevented from working in a low-efficiency area with low speed and low torque;

if the priority conditions do not meet the requirements of the required torque and SOC or are in a manual mode, a specific management strategy is formulated according to specific conditions, and specific descriptions of specific torque and SOC distribution principles are specified in a lower-layer torque distribution control layer;

step two, the lower layer torque distribution control layer comprises the following processes:

and obtaining the required torque according to the expected acceleration by a torque calculation formula, wherein the torque calculation formula is as follows:

T _req ＝(ma _x +mgf+C _D Av ² )

f rolling resistance coefficient; a is the windward area, namely the projection area of the driving direction of the automobile; c _D Is the air resistance coefficient; a is _x A desired acceleration (x =1,2,3,4,5,6); v represents the instantaneous speed of the vehicle; m represents the mass of the whole vehicle; g represents a unit of gravitational acceleration (N/kg);

judging the SOC value, and defining the SOC charging upper limit as SOC _max Lower limit of SOC discharge SOC _min Generally, the SOC charging upper limit value of the battery is selected as SOC _max =0.8, selecting the battery SOC discharge lower limit value SOC _min =0.3; in addition, there is an engine efficient operation interval with the upper limit of the interval being the maximum torque T of the engine _{e_max} The lower limit of the interval is the lowest starting torque T of the engine _{e_min} (ii) a The highest torque of the motor is T _{m_max} ；

When SOC > SOC _max When the required torque is less than the maximum torque T of the motor _{m_max} If the motor is driven independently, the SOC is reduced, and the SOC value is maintained in a certain range, so that the power battery pack works in a working interval with lower internal resistance and higher efficiency; the specific allocation strategy is as follows:

wherein, T _req Is the required torque; t is a unit of _e Is the engine torque; t is _m Is the motor torque;

if the required torque is greater than the maximum torque T of the motor _{m_max} If the engine is started, the motor and the engine are started simultaneously, and the part of the torque which cannot be provided by the engine is provided by the aid of the engine; the specific allocation strategy is as follows:

T _{m_max} the maximum torque of the motor;

when SOC is less than SOC _min Starting the engine to work in a high-efficiency working interval to output maximum torque, providing torque required by driving the vehicle to run, simultaneously charging the power battery pack by using residual power, and assisting the engine to provide the torque by using the motor; the specific allocation strategy is as follows:

T _{e_max} is the engine maximum torque;

when SOC is reached _min ＜SOC＜SOC _max If the required torque is in the high-efficiency working interval of the engine, enabling the engine to output the optimal torque, and if the engine cannot completely provide the required torque, providing the optimal torque by the aid of the motor; the specific allocation strategy is as follows:

T _{e_opt} the optimal working torque of the engine is obtained, and the engine works in a high-efficiency interval at the moment;

if the required torque is greater than the maximum torque T of the engine _{e_max} The engine outputs the highest torque, the required torque which cannot be provided by the engine is provided by the aid of the motor, and the specific distribution strategy is as follows:

if the required torque is less than the minimum torque T of the engine _{e_min} At the moment, the working efficiency of the engine under the low-load working condition is low, so that the engine is closed and is driven by the motor independently, and the specific distribution strategy is as follows:

the invention also provides a plug-in hybrid electric vehicle self-adaptive cruise energy management controller, which comprises an upper-layer multi-mode recognition and switching self-adaptive cruise mode controller, a middle-layer energy management method matching controller and a lower-layer torque distribution controller; the upper-layer multi-mode recognition and switching adaptive cruise mode control layer judges a cruise mode which a vehicle needs to be matched with and outputs expected acceleration under the current mode according to collected road traffic information, the middle-layer energy management method matching control layer preferentially distributes working modes of an engine and a motor under special road conditions according to the specific cruise mode matched with the upper-layer multi-mode recognition and switching adaptive cruise mode control layer and the distance from a destination, the lower-layer torque distribution control layer calculates required torque according to the expected acceleration output by the upper-layer multi-mode recognition and switching adaptive cruise mode control layer and judges whether the working modes of the engine and the motor preferentially distributed by the middle-layer energy management method matching control layer are reasonable according to a set rule, if not, other working modes are distributed, and the control layer can distribute the torques of the engine and the motor for all working conditions in the driving process.

Further, the adaptive cruise mode controller for upper-layer multi-mode identification and switching specifically comprises the following components:

judging whether the road condition belongs to a complex road condition mode or not through the curvature and gradient information,

judging which one of three cruise modes of a coasting cruise mode, a constant speed cruise mode and a following cruise mode is matched according to the speed of the front vehicle, the speed of the vehicle, the distance between the front vehicle and the vehicle and whether a traffic signal lamp exists in a certain distance and the state of the traffic signal lamp,

determining which cruise mode of six modes, namely a complex road condition sliding cruise mode, a non-complex road condition sliding cruise mode, a complex road condition constant speed cruise mode, a non-complex road condition constant speed cruise mode, a complex road condition following cruise mode and a non-complex road condition following cruise mode, should be entered under the current condition according to the judgment result; the specific judgment is as follows:

defining that when the curvature is zero, the road does not belong to the curve, when the curvature is not zero, the road section where the vehicle is located is the curve, and the corresponding expected acceleration is as follows:

a＝KV ²

v represents the vehicle over-bending speed during detection; k is the curvature;

when the gradient theta is zero, the road is a flat road without the gradient, and when the gradient theta is small

G/100 is a gradient, and G takes a positive value when the vehicle ascends, namely when the road section where the vehicle is located is a slope, the corresponding expected acceleration is as follows:

g represents the overall vehicle weight, i.e., G = mg (in N); g represents the acceleration of gravity (in N/kg);

only when the curvature K and the gradient theta are simultaneously zero, the cruise mode under the non-complex road condition is adopted, and the cruise mode under the complex road condition is adopted in other situations.

Defining L to represent whether a traffic signal lamp exists in a distance and a representation value of the state of the traffic signal lamp, wherein when L is 1, the traffic signal lamp exists in the road section and the road section is red, the vehicle should enter a sliding cruise mode, and the vehicle is in an X mode in the mode ₁ Within-distance adjustment of vehicle speed to V ₁ At this time, the distance from the vehicle to the traffic signal lamp is s _f At a distance s of the vehicle _f The internal neutral coasting depends on rolling resistance and air resistance to drive the vehicle speed from V ₁ And the speed is reduced to zero, and finally the speed is just zero at the position of a traffic signal lamp, wherein the sliding process relates to the energy change formula:

C _rr is the rolling resistance coefficient; theta is the road slope; ρ is the air density; a is the windward area, namely the projection area of the driving direction of the automobile; s _f A neutral glide distance; t is t _s Elapsed time for neutral coast; e _w Energy consumed in the sliding process; m is the mass of the whole vehicle; f _w Is a driving force; c _D Is the air resistance coefficient; v is the instantaneous speed at each moment under the influence of the deceleration generated by rolling resistance and air resistance during neutral coasting;

speed V when entering sliding mode ₁ Is composed of

when the speed of the vehicle is V and the distance between the vehicle and the signal lamp is S when the traffic signal lamp is detected to be red, X ₁ Is composed of

X ₁ ＝S-s _f

The specific acceleration calculation formula is as follows, namely the expected acceleration value of the non-complex road condition coasting cruise mode is as follows:

the expected acceleration value corresponding to the complex road condition coasting cruise mode is as follows:

definition ofDistance error Δ d = d-d _des Wherein d is the distance between the vehicle and the front vehicle at the moment, and delta d is the distance error; d _des To a desired vehicle distance, d _des Can be expressed as d _des ＝τ _h v+d ₀ Wherein tau is _h Time interval of the head of a vehicle, d ₀ V is the instantaneous speed of the vehicle in the process of driving at the minimum safe distance; defining the maximum distance d from the front vehicle _set Wherein d is _set ＝d _des + Δ x, wherein Δ x =1.5 × d _des ；

When d > d is satisfied _set ||d＜d _des The following vehicle cruise mode is entered, if d is larger than d _set Indicating that a distance from the front vehicle is far, a new expected acceleration adjustment and a distance d from the front vehicle should be generated _des If d is less than d _des It indicates that the distance to the front vehicle is closer and the new expected acceleration adjustment and the distance to the front vehicle d should be generated _des Speed, simultaneously adjusted to V _set ；

V represents the speed when the distance d from the front vehicle is detected, namely the expected acceleration value of the following cruise mode under the non-complex road condition is as follows:

the expected acceleration value of the following cruise mode under the complex road condition is as follows:

r is the wheel radius; n is the rotating speed of the engine working in the high-efficiency interval; i.e. i _g Is the transmission ratio of the transmission; i all right angle ₀ The transmission ratio of the main speed reducer is set;

when no traffic light or green traffic light is detected in the road section, the speed is V, the response time and the operation time of the driver are delta t, and the speed is adjusted to V _set The acceleration calculation formula in the process is as follows, namely the expected acceleration value in the following cruise mode under the non-complex road condition is as follows:

the vehicle acquires this trip distance before starting, if the trip distance is less than the vehicle pure electric range, then whole stroke gets into pure electric mode, realizes zero release, zero oil consumption's purpose, and battery SOC value reaches predetermined lower limit value when the stroke is ended, utilizes the big and advantage that can external electric wire netting charge of plug-in hybrid vehicle power battery group capacity to replenish the electric energy to make energy utilization rate the highest. And if the travel distance is greater than the pure electric cruising range of the vehicle or the travel distance is unclear, judging the value of the cruising mode M according to the adaptive cruising mode control layer identified and switched by the upper multi-mode, wherein the cruising mode is a coasting cruising mode when the value of M is defined to be 1, the constant-speed cruising mode when the value of M is 2, and the following cruising mode when the value of M is 3.

The lower-layer torque distribution control layer calculates required torque according to expected acceleration output by the upper-layer multi-mode recognition and switched adaptive cruise mode control layer and judges whether the priority working modes of the engine and the motor distributed by the middle-layer energy management method matching control layer are reasonable or not according to set rules, if not, other working modes are distributed, and meanwhile, the lower-layer torque distribution control layer can distribute the torque of the engine and the motor for all working conditions in the driving process.

When the vehicle is in the sliding cruise mode, the pure electric mode is preferably selected because the vehicle is mostly in a congested road section in a city road at the moment, the vehicle speed is low, and the vehicle is frequently accelerated and decelerated, so that the vehicle is driven by the motor to run under the low-speed and low-load working condition, and the engine is prevented from working in a low-efficiency region with low speed and low torque;

the specific pure electric mode is as follows:

wherein, T _req Is the required torque; t is _e Is the engine torque; t is _m Is the motor torque;

when the vehicle is in the constant-speed cruising mode, the vehicle mostly travels at medium and high speed, and the charging mode is preferably selected because the vehicle is positioned on suburban roads or high-speed road sections, the working efficiency is high and the working condition is stable without frequent acceleration and deceleration, and the set cruising speed ensures that the engine works in a high-efficiency area, and the surplus power is utilized to charge the power battery pack while the power required by driving the vehicle is provided;

the specific charging mode is as follows:

T _{e_max} is the engine maximum torque;

when the following cruise mode is adopted, the vehicle needs to be accelerated and decelerated frequently according to the distance from the front vehicle, and the vehicle works under the low-speed and low-load working condition at a lower speed, so that the pure electric mode is preferentially selected, the motor drives the vehicle to run independently, and the engine is prevented from working in a low-efficiency region with low speed and low torque;

if the priority conditions do not meet the required torque and SOC requirements or are in a manual mode, a lower-layer torque distribution control layer makes a specific management strategy according to specific conditions, and specific torque and SOC distribution principles are specifically described in the lower-layer torque distribution control layer;

the lower layer torque distribution control layer calculates the required torque according to the expected acceleration output by the upper layer multi-mode identification and switching self-adaptive cruise mode control layer, judges whether the priority working mode of the engine and the motor distributed by the middle layer energy management method matching control layer is reasonable according to the set rule, if not, distributes other working modes, and the control layer can distribute the torque of the engine and the motor for all working conditions involved in the driving process.

The lower layer torque distribution control layer obtains the required torque according to the expected acceleration by a torque calculation formula, and the specific expected acceleration a _x The value of (x =1,2,3,4,5,6) is calculated in the adaptive cruise mode control layer for upper layer multi-mode identification and switching, where the torque calculation formula is:

T _req ＝(ma _x +mgf+C _D Av ² )

f rolling resistance coefficient; a is the windward area, namely the projection area of the driving direction of the automobile; c _D Is the air resistance coefficient; a is a _x Is the desired acceleration (x =1,2,3,4,5,6); v represents the instantaneous speed of the vehicle; m represents the mass of the whole vehicle; g represents a unit of gravitational acceleration (N/kg);

judging the SOC value, and defining the SOC charging upper limit as SOC _max Lower limit of SOC discharge SOC _min Selecting the upper limit value of the SOC charge of the battery as SOC _max =0.8, selecting the battery SOC discharge lower limit value SOC _min =0.3; in addition, aiming at the high-efficiency working interval of the engine, the upper limit of the interval is defined as the highest torque T of the engine _{e_max} The lower limit of the interval is the minimum starting torque T of the engine _{e_min} ；

When SOC > SOC _max If torque is requiredLess than maximum torque T of motor _{m_max} The engine is independently driven, the SOC is reduced at the moment, and the SOC value is maintained in a certain range, so that the power battery pack works in a working interval with lower internal resistance and higher efficiency; the specific allocation strategy is as follows:

T _e is the engine torque; t is _m Is the motor torque; t is _req Is the required torque;

T _{m_max} is the motor maximum torque;

T _{e_max} is the engine maximum torque;

T _{e_opt} the optimal working torque is the engine, and the engine works in a high-efficiency interval at the moment;

if the required torque is greater than the maximum torque T of the engine _{e_max} The engine outputs the highest torque, and the required torque which cannot be provided by the engine is provided by the assistance of the motor; the specific allocation strategy is as follows:

if the required torque is less than the minimum torque T of the engine _{e_min} At the moment, the working efficiency of the engine under the low-load working condition is low, so that the engine is closed and is driven by the motor independently; the specific allocation strategy is as follows:

the invention has the beneficial effects that:

1. the adaptive cruise control system and the adaptive cruise control method aim at different working conditions and road conditions to design the adaptive cruise control strategy corresponding to the working conditions and the road conditions, and generate corresponding expected acceleration.

2. The PHEV is added with a charging function of an external power grid on the basis of the HEV, can run for a long distance in a pure electric mode, and can be in a hybrid power mode when needed, so that corresponding self-adaptive cruise modes under different road conditions are designed to break through the limitation that related technical research is still independently carried out in the fields of new energy vehicles and intelligent vehicles at present, and the self-adaptive cruise modes are matched with energy distribution modes of different hybrid power vehicles to realize maximum utilization of energy.

3. The invention matches the corresponding plug-in hybrid vehicle energy management strategy according to the specific cruise control strategy and the expected acceleration so that the energy management strategy can fully consume the electric quantity of the battery in one trip or before the next charging and the fuel consumption is reduced during the high-efficiency working period of the engine.

Drawings

FIG. 1 is a schematic diagram of the overall distribution of the strategy of the present invention;

FIG. 2 illustrates the expected acceleration for different cruise modes according to the present invention;

FIG. 3 illustrates the energy management strategy to be matched for each cruise mode of the present invention;

FIG. 4 is a diagram of the present invention for torque and SOC matching rules;

FIG. 5 is a coast cruise mode of the present invention;

FIG. 6 illustrates the curve road condition of the present invention;

FIG. 7 shows the road condition of the ramp according to the present invention;

FIG. 8 is the constant speed cruise mode of the present invention;

FIG. 9 illustrates a vehicle following cruise mode of the present invention;

Detailed Description

The invention will be further described with reference to the following figures and specific examples, without limiting the scope of the invention thereto.

A self-adaptive cruise energy management method for a plug-in hybrid electric vehicle mainly obtains road traffic information through a vehicle-mounted Global Positioning System (GPS), a Geographic Information System (GIS), an Intelligent Transportation System (ITS), a vehicle speed sensor laser radar and the like, wherein the road traffic information comprises gradient, curvature, distance with a front vehicle, speed of the front vehicle, whether a traffic signal lamp and a state of the traffic signal lamp exist in a certain distance, and running state information of the vehicle, and the self-adaptive cruise energy management method comprises the following steps: the speed of the vehicle, the SOC of the vehicle and the like, and then a corresponding energy management method is designed according to different cruise modes by considering road condition information.

The invention relates to a self-adaptive cruise energy management method for a plug-in hybrid electric vehicle, which comprises the following steps of:

step one, collecting road traffic information: the real-time collection of road traffic information of a vehicle through a vehicle-mounted Global Positioning System (GPS), a Geographic Information System (GIS), an Intelligent Traffic System (ITS), a vehicle speed sensor laser radar and the like comprises the following steps: slope, camber, with the distance of preceding car, preceding car speed, whether have traffic signal lamp and state in certain distance to and the running state information of car certainly, include: vehicle speed and vehicle SOC.

Step two, designing a self-adaptive cruise energy hierarchical management strategy of the plug-in hybrid electric vehicle: the adaptive cruise energy hierarchical manager mainly comprises an upper-layer multi-mode recognition and switching adaptive cruise mode control layer, a middle-layer energy management method matching control layer and a lower-layer torque distribution control layer; as shown in fig. 1, the upper layer multi-mode recognition and switched adaptive cruise control layer judges the cruise mode matched with the vehicle and outputs the expected acceleration in the current mode according to the collected road traffic information, the middle layer energy management method matching control layer preferentially allocates the working mode of the engine and the motor under the special road conditions according to the specific cruise mode matched with the upper layer multi-mode recognition and switched adaptive cruise control layer and the distance from the destination, the lower layer torque allocation control layer calculates the required torque according to the expected acceleration output by the upper layer multi-mode recognition and switched adaptive cruise control layer and judges the transmission mode preferentially allocated by the middle layer energy management method matching control layer according to the set rule

Further, the second step of the upper layer multi-mode recognition and switching adaptive cruise mode control layer comprises the following processes:

as shown in fig. 2, it is determined whether the road condition belongs to a complex road condition mode according to the input curvature and gradient information, then it is determined whether a cruise mode of a taxi cruise mode, a constant speed cruise mode and a follow cruise mode should be matched according to the input vehicle speed of the preceding vehicle, the vehicle speed of the vehicle, the distance to the preceding vehicle and the presence or absence of a traffic signal lamp within a certain distance and the state thereof, and finally it is determined that the cruise mode of the taxi cruise mode, the non-complex road condition taxi cruise mode, the complex road condition constant speed cruise mode, the non-miscellaneous road condition constant speed cruise mode, the complex road condition follow cruise mode, the non-complex road condition follow cruise mode and the cruise mode under the condition should be entered according to the above information. The specific values and the principles of the expected acceleration corresponding to different cruise modes are determined as follows:

defining that when the curvature is zero, the road does not belong to a curve, and when the curvature is not zero, the road section where the vehicle is located is a curve, as shown in fig. 6, the corresponding expected acceleration is:

a＝KV ²

G/100 is a gradient, and G takes a positive value when the vehicle is ascending, that is, when the road section where the vehicle is located is a slope, as shown in fig. 7, the corresponding expected acceleration is:

g represents the vehicle weight, i.e., G = mg (in N), and m represents the vehicle mass; g represents the acceleration of gravity (in N/kg);

therefore, the cruise mode under the non-complex road condition is only adopted when the curvature K and the gradient theta are simultaneously zero, the cruise mode under the complex road condition is adopted in other situations, and the road condition conditions need to be considered when the expected acceleration under the cruise mode is calculated.

Defining L as a value indicating whether there is a traffic light and its status in a certain distance, and when L is 1, it indicates that there is a traffic light and it is red light in the road section, and at this time, the vehicle should enter a taxi cruise mode, as shown in FIG. 5, in which the vehicle is in X mode ₁ Within-distance adjustment of vehicle speed to V ₁ At this time, the distance from the vehicle to the traffic signal lamp is s _f At a distance s of the vehicle _f The internal neutral coasting depends on rolling resistance and air resistance to drive the vehicle speed from V ₁ And (3) dropping to zero, and finally, just taking the speed as zero at a traffic signal lamp, wherein the sliding process relates to an energy change formula as follows:

C _rr is the rolling resistance coefficient; theta is the road gradient; ρ is the air density; a is the windward area, namely the projection area of the driving direction of the automobile; s _f A neutral glide distance; t is t _s Elapsed time for neutral coast;E _w energy consumed in the sliding process; m is the mass of the whole vehicle; f _w Is a driving force; c _D Is the air resistance coefficient; v is the instantaneous speed at each moment under the influence of the deceleration generated by rolling resistance and air resistance during neutral coasting;

speed V when entering the sliding mode ₁ Is composed of

X ₁ ＝S-s _f

The specific acceleration calculation formula is as follows, that is, as shown in fig. 2, the expected acceleration value in the cruise mode under non-complex road conditions is as follows:

the expected acceleration value of the complex road condition coasting cruise mode is as follows:

defining a distance error Δ d = d-d _des Wherein d is the distance between the vehicle and the front vehicle at the moment, and delta d is the distance error; d _des To a desired vehicle distance, d _des Can be expressed as d _des ＝τ _h v+d ₀ Wherein tau is _h Time interval of the head of a vehicle, d ₀ V is the instantaneous speed of the vehicle in the process of driving at the minimum safe distance; definition of the best distance from the front vehicleA large distance d _set Wherein d is _set ＝d _des + Δ x, where Δ x =1.5 × d _des ；

When d > d is satisfied _set ||d＜d _des The following cruise mode is entered, as shown in FIG. 9, if d > d _set Indicating that a distance from the front vehicle is far, a new expected acceleration adjustment and a distance d from the front vehicle should be generated _des If d is less than d _des It indicates that the distance to the front vehicle is closer and the new expected acceleration adjustment and the distance to the front vehicle d should be generated _des ；

As shown in fig. 2, V represents the speed detected when the distance d from the front vehicle is detected, and the expected acceleration value in the non-complex road condition following vehicle cruise mode is:

when d is satisfied _des ≤d≤d _set The cruise control mode is entered at the time, in which the control target of the vehicle speed is the cruise vehicle speed V set by the driver as shown in fig. 8 _set In which V is _set The specific values are:

r is the wheel radius; n is the rotating speed of the engine working in the high-efficiency interval; i all right angle _g Is the transmission ratio of the transmission; i.e. i ₀ Is the transmission ratio of the main reducer;

when detecting that no traffic light exists in the road section or the traffic light is green, the speed is V, the response time of the driver is delta t, and the speed is adjusted to V _set The calculation formula of the acceleration in the process is as follows, as shown in fig. 2, that is, the expected acceleration value in the following cruise mode under the non-complex road condition is:

the step two, matching the control layer with the layer energy management method, comprises the following processes:

as shown in fig. 3, the vehicle obtains the travel distance before departure, and if the travel distance is less than the vehicle electric range, the entire travel enters an electric mode, so as to achieve the purposes of zero emission and zero fuel consumption, and when the travel is finished, the SOC value of the battery reaches a preset lower limit value, and the electric energy is supplemented by using the advantages that the capacity of the plug-in hybrid electric vehicle power battery pack is large and the battery can be charged by an external power grid, so that the energy utilization rate is highest. And if the travel distance is greater than the pure electric cruising range of the vehicle or the travel distance is unclear, judging the value of the cruising mode M according to the adaptive cruising mode control layer identified and switched by the upper multi-mode, wherein the cruising mode is a coasting cruising mode when the value of M is defined to be 1, the constant-speed cruising mode when the value of M is 2, and the following cruising mode when the value of M is 3.

The middle-layer energy management method is characterized in that the matching control layer of the middle-layer energy management method mainly allocates the optimal working modes of the engine and the motor under several special working conditions according to the specific cruise mode matched with the self-adaptive cruise mode control layer which is subjected to multi-mode identification and switching at the upper layer and the distance from a destination, the lower-layer torque allocation control layer calculates the required torque according to the expected acceleration output by the self-adaptive cruise mode control layer which is subjected to multi-mode identification and switching at the upper layer and judges whether the priority working modes of the engine and the motor allocated by the matching control layer of the middle-layer energy management method are reasonable according to the set rules, if not, other working modes are allocated, and the control layer can allocate the torque of the engine and the motor to all the working conditions in the driving process.

the specific pure electric mode is as follows:

wherein, T _req Is the required torque; t is a unit of _e Is the engine torque; t is a unit of _m Is the motor torque;

when the vehicle is in a constant-speed cruising mode, the vehicle mostly runs at a medium-high speed, and the charging mode is preferably selected because the vehicle is positioned on suburban roads or high-speed road sections, the working efficiency is high and the working condition is stable without frequent acceleration and deceleration, and the set cruising speed ensures that the engine works in a high-efficiency area, and the surplus power is used for charging the power battery pack while the power required for driving the vehicle is provided;

the specific charging mode is as follows:

T _{e_max} is the engine maximum torque;

when the following cruise mode is adopted, the vehicle needs to be accelerated and decelerated frequently according to the distance from the front vehicle, and the vehicle works under the low-speed low-load working condition at a low speed, so that the pure electric mode is preferentially selected, the motor is used for driving the vehicle to run independently, and the engine is prevented from working in a low-efficiency area with low speed and low torque;

the second lower layer torque distribution control layer comprises the following processes:

the lower layer torque distribution control layer calculates the required torque according to the expected acceleration output by the upper layer multi-mode recognition and switching self-adaptive cruise mode control layer, judges whether the priority working mode of the engine and the motor distributed by the middle layer energy management method matching control layer is reasonable according to the set rule, if not, distributes other working modes, and the control layer can distribute the torque of the engine and the motor for all working conditions involved in the driving process.

As shown in FIG. 4, the lower torque distribution control layer derives the required torque from a torque calculation formula according to the desired acceleration, specifically the desired acceleration a _x Is shown in fig. 2, wherein the torque calculation formula is:

T _req ＝(ma _x +mgf+C _D Av ² )

judging the SOC value, and defining the SOC charging upper limit as the SOC _max Lower limit of SOC discharge SOC _min Selecting the upper limit value of the SOC charge of the battery as SOC _max =0.8, selecting the battery SOC discharge lower limit value SOC _min =0.3; in addition, aiming at the high-efficiency working interval of the engine, the upper limit of the interval is defined as the highest torque T of the engine _{e_max} The lower limit of the interval is the lowest starting torque T of the engine _{e_min} ；

When SOC > SOC _max If the required torque is less than the maximum torque T of the motor _{m_max} The engine is independently driven, the SOC is reduced at the moment, the SOC value is maintained in a certain range, the power battery pack works in a working interval with lower internal resistance and higher efficiency, and a specific allocation strategy is as follows:

if the required torque is greater than the maximum torque T of the motor _{m_max} And simultaneously starting the motor and the engine, wherein the part of the torque which cannot be provided by the engine is provided by the assistance of the engine, and the specific distribution strategy is as follows:

T _{m_max} the maximum torque of the motor;

when SOC is less than SOC _min And starting the engine to work in an efficient working range to output maximum torque, providing torque required by driving the vehicle to run, simultaneously utilizing the surplus power to charge the power battery pack, and assisting the engine to provide the torque by the motor, wherein the specific allocation strategy is as follows:

T _{e_max} is the engine maximum torque;

when SOC is reached _min ＜SOC＜SOC _max If the required torque is in the efficient working interval of the engine, the engine outputs the optimal torque, and if the engine cannot completely provide the required torque, the required torque is provided by the aid of the motor, and the specific distribution strategy is as follows:

the above-listed detailed description is only a specific description of a possible embodiment of the present invention, and it is not intended to limit the scope of the present invention, and equivalents and modifications not departing from the technical spirit of the present invention should be included in the scope of the present invention.

Claims

1. The adaptive cruise energy management method of the plug-in hybrid electric vehicle is characterized by comprising an adaptive cruise mode control layer, a middle layer energy management method matching control layer and a lower layer torque distribution control layer, wherein the adaptive cruise mode control layer is designed for upper layer multi-mode recognition and switching; the upper-layer multi-mode recognition and switching adaptive cruise mode control layer judges a cruise mode which a vehicle needs to be matched with and outputs expected acceleration under the current mode according to collected road traffic information, the middle-layer energy management method matching control layer preferentially distributes working modes of an engine and a motor under special road conditions according to a specific cruise mode which is matched with the upper-layer multi-mode recognition and switching adaptive cruise mode control layer and a distance away from a destination, the lower-layer torque distribution control layer calculates required torque according to the expected acceleration which is output by the upper-layer multi-mode recognition and switching adaptive cruise mode control layer and judges whether the working modes of the engine and the motor which are preferentially distributed by the middle-layer energy management method matching control layer are reasonable or not according to a set rule, if not, other working modes are distributed, and the control layer can distribute the torques of the engine and the motor for all working conditions in the driving process;

the design method of the adaptive cruise control layer for the upper multi-mode identification and switching specifically comprises the following steps:

s2.1, judging whether the road condition belongs to a complex road condition mode or not through the input curvature and gradient information;

s2.2, judging which one of the three cruise modes of the coasting cruise mode, the constant-speed cruise mode and the following cruise mode should be matched according to the input speed of the front vehicle, the speed of the vehicle, the distance between the vehicle and the front vehicle, whether a traffic signal lamp exists in a certain distance and the state of the traffic signal lamp;

s2.3, finally determining which cruising mode of the complex road condition sliding cruising mode, the non-complex road condition sliding cruising mode, the complex road condition constant speed cruising mode, the non-complex road condition constant speed cruising mode, the complex road condition following cruising mode and the non-complex road condition following cruising mode is to be entered according to the information;

wherein, the method for judging whether the road condition belongs to the complex road condition mode in the S2.1 comprises the following steps:

the method for judging which cruise mode of the three cruise modes is matched in the S2.2 comprises the following steps: defining L to represent whether a traffic signal lamp exists in a distance and a representation value of the state of the traffic signal lamp, when the L is 1, the traffic signal lamp exists in the road section and the road section is a red light, at the moment, the vehicle should enter a sliding cruise mode, in the mode, the vehicle adjusts the vehicle speed to V1 within the newly expected acceleration generated by the vehicle in the X1 distance, and the speed can be ensured to be within the distance s _f Internal neutral coasting relies on rolling and air resistance to slow down the vehicle to just zero speed at the traffic light, where

C _rr Is the rolling resistance coefficient; theta is the road grade; rhoIs the air density; a is the windward area, namely the projection area of the driving direction of the automobile; m is the mass of the whole vehicle; f _w Is a driving force; c _D Is the air resistance coefficient; v represents the instantaneous speed at each moment during the driving; during taxi cruise, at t _s Distance s traveled in time _f Energy calculation equation E involved _w Comprises the following steps:

s _f a neutral glide distance; t is t _s Elapsed time for neutral coast; e _w Energy consumed in the sliding process; v is the instantaneous speed at each moment under the influence of the deceleration generated by rolling resistance and air resistance during neutral coasting; g represents the gravitational acceleration;

defining a distance error Δ d = d-d _des Wherein d is the distance between the vehicle and the front vehicle at the moment, and delta d is the distance error; d _des To a desired vehicle distance, d _des Can be expressed as d _des ＝τ _h v+d ₀ Wherein τ is _h Time interval of the head of a vehicle, d ₀ V is the instantaneous speed of the vehicle in the process of driving at the minimum safe distance; defining the maximum distance d from the front vehicle _set Wherein d is _set ＝d _des + Δ x, wherein Δ x =1.5 × d _des ；

When d > d is satisfied _set ||d＜d _des Entering a following cruise mode if d is larger than d _set Indicating that a distance from the front vehicle is far, a new expected acceleration adjustment and a distance d from the front vehicle should be generated _des If d is less than d _des It indicates that the distance to the front vehicle is closer and the new expected acceleration adjustment and the distance to the front vehicle d should be generated _des The speed is simultaneously adjusted to V _set ；

When d is satisfied _des ≤d≤d _set The constant speed cruising mode is entered, and the method is in the constant speed cruising modeThe vehicle generates a new expected acceleration to adjust the existing speed to the cruising speed V set by the driver _set 。

2. The adaptive cruise energy management method for the plug-in hybrid electric vehicle according to claim 1, further comprising the step of collecting road traffic information where the vehicle is located in real time, wherein the step of collecting the road traffic information comprises the following steps: slope theta, camber K, with the distance of preceding car, the preceding car speed of a motor vehicle, whether have traffic signal lamp and state in certain distance to and gather the running state information of own car in real time, include: the vehicle speed and the vehicle SOC.

3. The plug-in hybrid electric vehicle adaptive cruise energy management method according to claim 1, characterized in that the design method of the middle layer energy management method matching the control layer is as follows:

the vehicle obtains the travel distance before starting, and if the travel distance D is less than the pure electric endurance mileage D of the vehicle _m If the travel distance is greater than the pure electric cruising range of the vehicle or the travel distance is not clear, judging the value of M according to an adaptive cruise mode control layer identified and switched by an upper layer of multi-mode, wherein the value of M is defined as a sliding cruise mode when the value of M is 1, the value of M is defined as a following cruise mode when the value of M is 2, and the value of M is defined as a constant speed cruise mode when the value of M is 3;

when the vehicle is in the sliding cruise mode, the pure electric mode is preferentially selected on the premise that the vehicle speed of a congested road section, where the vehicle is mostly located in a road in a city area, is low and the vehicle is frequently accelerated and decelerated under the condition that the vehicle accords with the torque and the SOC, and the vehicle is driven to run by the motor under the low-speed and low-load working condition, so that the engine is prevented from working in a low-efficiency region with low speed and low torque;

when the following cruise mode is adopted, the vehicle needs to be accelerated and decelerated frequently according to the distance from the front vehicle, and the vehicle speed is low, so that the vehicle works under the working condition of low speed and low load, therefore, the pure electric mode is preferentially selected on the premise of meeting the torque and the SOC, the motor is used for driving the vehicle to run independently, and the engine is prevented from working in the low-efficiency region of low speed and low torque.

4. The adaptive cruise energy management method for the plug-in hybrid electric vehicle according to claim 1, wherein the design method of the lower torque distribution control layer is specifically as follows:

T _req ＝(ma _x +mgf+C _d Av ² )

judging the SOC value, and defining the SOC charging upper limit as SOC _max Lower limit of SOC discharge SOC _min Selecting the upper limit value of the SOC charge of the battery as SOC _max =0.8, selecting the battery SOC discharge lower limit value SOC _min =0.3; in addition, aiming at the high-efficiency working interval of the engine, the upper limit of the interval is defined as the highest torque T of the engine _{e_max} The lower limit of the interval is the lowest starting torque T of the engine _{e_min} The highest torque of the motor is T _{m_max} ；

When SOC > SOC _max When the required torque is less than the maximum torque T of the motor _{m_max} The motor is driven alone, and the SOC is reducedThe SOC value is maintained in a certain range, so that the power battery pack works in a working interval with lower internal resistance and higher efficiency; the specific allocation strategy is as follows:

if the required torque is greater than the maximum torque T of the motor _{m_max} If the motor and the engine are started simultaneously, the motor outputs the highest torque, and the part of the torque which cannot be provided by the motor is provided by the assistance of the engine; the specific allocation strategy is as follows:

T _{m_max} the maximum torque of the motor;

T _{e_max} is the engine maximum torque;

if the required torque is greater than the maximum torque T of the engine _{e_max} The engine outputs the highest torque, and the required torque which cannot be provided by the engine is provided by the aid of the motor; the specific allocation strategy is as follows:

5. the adaptive cruise energy management controller of the plug-in hybrid electric vehicle is characterized by comprising an adaptive cruise mode controller for upper-layer multi-mode identification and switching, a middle-layer energy management method matching controller and a lower-layer torque distribution controller; the upper-layer multi-mode recognition and switching adaptive cruise mode control layer judges a cruise mode which a vehicle needs to be matched with and outputs expected acceleration under the current mode according to collected road traffic information, the middle-layer energy management method matching control layer preferentially distributes working modes of an engine and a motor under special road conditions according to the specific cruise mode matched with the upper-layer multi-mode recognition and switching adaptive cruise mode control layer and the distance from a destination, the lower-layer torque distribution control layer calculates required torque according to the expected acceleration output by the upper-layer multi-mode recognition and switching adaptive cruise mode control layer and judges whether the working modes of the engine and the motor preferentially distributed by the middle-layer energy management method matching control layer are reasonable according to a set rule, if not, other working modes are distributed, and the control layer can distribute the torques of the engine and the motor for all working conditions in the driving process.

6. The adaptive cruise energy management controller for the plug-in hybrid electric vehicle according to claim 5, wherein the adaptive cruise mode controller for the upper multi-mode recognition and switching comprises the following specific steps:

determining which cruise mode of six modes, namely a complex road condition sliding cruise mode, a non-complex road condition sliding cruise mode, a complex road condition constant speed cruise mode, a non-miscellaneous road condition constant speed cruise mode, a complex road condition vehicle following cruise mode and a non-complex road condition vehicle following cruise mode, should be entered under the current condition according to the judgment result; the specific judgment is as follows:

a＝KV ²

v represents the speed detected when the vehicle passes a curve; k is the curvature;

when the gradient theta is zero, the road is level when no gradient exists, and when the gradient theta is very small, the road is smooth

g represents the overall vehicle weight, i.e. G = mg, in N; g represents the gravity acceleration and has the unit of N/kg;

only when the curvature K and the gradient theta are simultaneously zero, the cruise mode under the non-complex road condition is adopted, and the cruise mode under the complex road condition is adopted in other situations;

defining L to represent whether a traffic signal lamp exists in a distance and a representation value of the state of the traffic signal lamp, wherein when L is 1, the traffic signal lamp exists in the road section and the road section is red, the vehicle should enter a sliding cruise mode, and the vehicle is in an X mode in the mode ₁ Within-distance vehicle speed is adjusted to be V ₁ At this time, the distance from the vehicle to the traffic signal lamp is s _f At a distance s of the vehicle _f The internal neutral coasting depends on rolling resistance and air resistance to drive the vehicle speed from V ₁ And the speed is reduced to zero, and finally the speed is just zero at the position of a traffic signal lamp, wherein the sliding process relates to the energy change formula:

C _rr is the rolling resistance coefficient; theta is the road gradient; ρ is the air density; a is the windward area, namely the projection area of the driving direction of the automobile; s _f A neutral glide distance; t is t _s Elapsed time for neutral coast; e _w Energy consumed in the sliding process; m is the mass of the whole vehicle; f _w Is a driving force; c _D Is the air resistance coefficient; v is the instantaneous speed at each moment under the influence of the deceleration generated by rolling resistance and air resistance during neutral coasting;

speed V when entering sliding mode ₁ Is composed of

when the traffic signal lamp is detected to be red, the speed of the vehicle is V, and the vehicle and the traffic signal lamp are connectedDistance of signal lamp is S, then X ₁ Is composed of

X ₁ ＝S-s _f

the corresponding complex road condition coasting cruise mode expected acceleration value is as follows:

defining a distance error Δ d = d-d _des Wherein d is the distance between the vehicle and the front vehicle at the moment, and delta d is the distance error; d _des To a desired vehicle distance, d _des Can be expressed as d _des ＝τ _h v+d ₀ Wherein tau is _h Time interval of the head of a vehicle, d ₀ V is the instantaneous speed of the vehicle in the process of driving at the minimum safe distance; defining the maximum distance from the front vehicle as a _set Wherein d is _set ＝d _des + Δ x, wherein Δ x =1.5 × d _des ；

When the distance between the vehicle and the front vehicle is detected to be d, the speed of the vehicle is detected to be V, namely the expected acceleration value of the following cruise mode under the non-complex road condition is as follows:

r is the wheel radius; n is the rotating speed of the engine working in the high-efficiency interval; i all right angle _g Is the transmission ratio of the transmission; i.e. i ₀ The transmission ratio of the main speed reducer is set;

when detecting that no traffic light exists in the road section or the traffic light is green, the speed is V, the response time of the driver is delta t, and the speed is adjusted to V _set The acceleration calculation formula in the process is as follows, namely the expected acceleration value of the following cruise mode under the non-complex road condition is as follows:

7. the adaptive cruise energy management controller of a plug-in hybrid electric vehicle according to claim 5, wherein the middle layer energy management strategy matching controller is specifically as follows:

the method comprises the steps that a vehicle obtains a travel distance before starting, if the travel distance is smaller than a pure electric driving range of the vehicle, the whole travel enters a pure electric mode, the purposes of zero emission and zero oil consumption are achieved, the SOC value of a battery reaches a preset lower limit value when the travel is finished, and electric energy is supplemented by utilizing the advantages that the capacity of a power battery pack of the plug-in hybrid electric vehicle is large and the power battery pack can be charged by an external power grid, so that the energy utilization rate is highest; if the travel distance is greater than the pure electric cruising range of the vehicle or the travel distance is unclear, judging the value of a cruising mode M according to an adaptive cruising mode control layer which is identified and switched by an upper layer of multi-modes, wherein the cruising mode is a sliding cruising mode when the value of M is defined to be 1, the constant-speed cruising mode when the value of M is 2, and the following cruising mode when the value of M is 3;

the specific pure electric mode is as follows:

wherein, T _req Is the required torque; t is _e Is the engine torque; t is a unit of _m Is the motor torque;

when the vehicle is in the constant-speed cruising mode, the vehicle mostly travels at medium and high speeds, and the vehicle is positioned on suburban roads or high-speed road sections, so that the charging mode is preferentially selected on the premise of meeting the torque and SOC (state of charge), the set cruising speed ensures that the engine works in a high-efficiency area, and the surplus power is utilized to charge the power battery pack while the power required for driving the vehicle is provided;

the specific charging mode is as follows:

T _{e_max} is the engine maximum torque;

when the following cruise mode is adopted, the vehicle needs to be accelerated and decelerated frequently according to the distance from the front vehicle, and the vehicle speed is low, so that the vehicle works in a low-speed low-load working condition, therefore, the pure electric mode is preferentially selected on the premise of meeting the torque and the SOC, the vehicle is driven by the motor to run independently, and the engine is prevented from working in a low-efficiency area with low speed and low torque.

8. The adaptive cruise energy management controller for a plug-in hybrid vehicle according to claim 5, wherein the lower torque distribution controller is specifically as follows:

the lower layer torque distribution control layer obtains the required torque according to the expected acceleration through a torque calculation formula, and the specific expected acceleration a _x The value of (x =1,2,3,4,5,6) is calculated in the adaptive cruise mode control layer for upper layer multi-mode identification and switching, where the torque calculation formula is:

T _req ＝(ma _x +mgf+C _D Av ² )

judging the SOC value, and defining the SOC charging upper limit as SOC _max Lower limit of SOC discharge SOC _min Selecting the upper limit value of the SOC charge of the battery as SOC _max =0.8, selecting the battery SOC discharge lower limit value SOC _min =0.3; in addition, aiming at the high-efficiency working interval of the engine, the upper limit of the interval is defined as the highest torque T of the engine _{e_max} The lower limit of the interval is the lowest starting torque T of the engine _{e_min} ；

When SOC > SOC _max If the required torque is less thanMaximum torque T of motor _{m_max} If the motor is driven independently, the SOC is reduced, the SOC value is maintained in a certain range, and the power battery pack works in a working interval with lower internal resistance and higher efficiency; the specific allocation strategy is as follows:

if the required torque is greater than the maximum torque T of the motor _{m_max} The electric motor and the engine are started simultaneously, and the part of the torque which cannot be provided by the engine is provided by the aid of the engine; the specific allocation strategy is as follows:

if the required torque is greater than the maximum torque T of the engine _{e_max} Then the engine output is highestTorque, the required torque that cannot be provided by the engine is provided by the assistance of the electric motor; the specific allocation strategy is as follows: