A new energy electric trailer energy consumption optimization method

Abstract

The present application relates to a kind of new energy electric trailer energy consumption optimization method, electric trailer and tractor carry out CAN communication, obtain the throttle pedal opening signal Acc of tractor, brake pedal opening signal Bsk, the gear panel signal of tractor, hand brake signal, vehicle speed signal Velocity, and based on the above parameters obtain the driving behavior of driver and whole vehicle working condition, according to different speed interval and driving behavior, judge whether electric trailer needs large power, if need then enter brake mode or driving assist mode, calculate output motor brake torque, if not, then according to different speed interval set different motor compensation torque, control motor output motor compensation torque, to avoid trailer motor idling in the process of travel and produce very big field weakening current, effectively reduce the power loss generated by field weakening current under driving condition, optimize whole vehicle energy consumption, improve whole vehicle economy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle driving, and more particularly to a new energy electric trailer energy consumption optimization method. BACKGROUND

[0002] In the automobile transportation industry, the traditional trailer originally refers to a transport vehicle without a power driving device, which needs to rely on the traction power provided by the tractor to realize the driving for carrying passengers or goods. With the electrification and intelligentization process of the automobile industry, the new energy electric trailer has become a new development trend.

[0003] The new energy electric trailer is based on the traditional trailer integrated with a power device, which can output driving force to provide assistance to the tractor to jointly drive the whole vehicle to run, effectively improving the power performance of the whole vehicle in adverse working conditions. When braking, the rear-end electric trailer can also participate in braking to realize brake energy recovery, improve the economy of the whole vehicle, and reduce heat loss waste. However, the new energy electric trailer does not need to provide assistance in all driving conditions. When the tractor is running, if the electric trailer does not participate in driving and braking, the motor of the electric trailer will be idling with the tractor, especially at high speed to suppress the induced electromotive force generated. At this time, the motor will generate a weak magnetic current at the end, which is similar to a load. Even if there is no output driving and braking torque, it will also cause power loss and energy waste. SUMMARY

[0004] The present application aims to provide a new energy electric trailer energy consumption optimization method to solve the above problems.

[0005] The present application adopts the following technical solutions:

[0006] A new energy electric trailer energy consumption optimization method, the electric trailer VCU and the tractor VCU perform CAN communication, the electric trailer VCU obtains the accelerator pedal opening degree signal parameter Acc, the brake pedal opening degree signal parameter Bsk, the tractor gear panel signal, the hand brake signal and the vehicle speed signal parameter Velocity of the tractor VCU, and the specific steps of the electric trailer energy consumption optimization are as follows:

[0007] Step one, the electric trailer is powered on, and the whole vehicle enters the GO mode.

[0008] Step two, in the GO mode of the whole vehicle, the hand brake signal and the tractor gear panel signal are judged. If the hand brake signal = 0, i.e. the hand brake is released, and the tractor gear panel signal is in the forward gear, the whole vehicle enters the running mode.

[0009] Step three, when the electric trailer gets Bsk>0, the whole vehicle enters the braking mode, the electric trailer VCU gets the coefficient K according to the brake pedal opening and the vehicle speed interpolation table table1, and gets the current maximum output torque Torque_max according to the motor model, and calculates the output motor braking torque TM_rq as: TM_rq=K*Torque_max.

[0010] Step four, when the electric trailer Acc>0, the electric trailer enters the driving mode, according to different vehicle speed intervals and the throttle pedal opening signal and the vehicle acceleration in the vehicle speed interval, it is judged whether the electric trailer enters the driving assist mode, if it enters the driving assist mode, the output motor braking torque is calculated according to the throttle pedal opening and the vehicle speed interpolation table table2, if it does not enter the driving mode, different motor compensation torques are set according to different vehicle speed intervals, and the electric trailer VCU controls the output motor braking torque to be equal to the set motor compensation torque.

[0011] Further, the traction vehicle gear panel signal includes forward gear, reverse gear and neutral gear.

[0012] Further, in step four, the vehicle high-speed working condition threshold parameter Vb, the vehicle medium-speed working condition threshold parameter Vm, the high-speed working condition vehicle acceleration threshold parameter a1, the medium-speed working condition vehicle acceleration threshold parameter a2, the low-speed working condition vehicle acceleration threshold parameter a3, the throttle pedal opening calibration threshold parameter b, the calibration high-speed working condition cumulative Acc>b time threshold parameter t1, the calibration medium-speed working condition cumulative Acc>b time threshold parameter t2, and the calibration low-speed working condition cumulative Acc>b time threshold parameter t3 are set, and different motor braking torques or field weakening current compensation torques are calculated according to different vehicle speed intervals, and the specific steps are as follows:

[0013] 1) When the vehicle speed obtained by the electric trailer VCU satisfies Velocity>Vb, it is determined that it is a high-speed working condition, and under the high-speed working condition, if Acc>b and the duration is greater than t1 and the vehicle acceleration Vech_a is less than a1, the driving assist mode is entered, the electric trailer VCU gets the coefficient k according to the throttle pedal opening and the vehicle speed interpolation table table2, and calculates the output motor braking torque TM_rq as: TM_rq=k*Torque_max; if Acc>b and the duration is greater than t1 and the vehicle acceleration Vech_a is less than a1 are not met, the motor compensation torque T1 is set, and the electric trailer VCU controls the output motor braking torque TM_rq as: TM_rq=T1.

[0014] 2) When the vehicle speed obtained by the electric trailer VCU satisfies Vb>Velocity>Vm, it is determined that the medium-speed working condition is met. Under the medium-speed working condition, if Acc>b and the duration is longer than t2 and the vehicle acceleration Vech_a<a2, the drive assist mode is entered, the electric trailer VCU obtains the coefficient k according to the accelerator pedal opening degree and the vehicle speed interpolation coefficient table table2, and calculates the output motor braking torque TM_rq as TM_rq=k*Torque_max; if Acc>b and the duration is longer than t2 and the vehicle acceleration Vech_a<a2, the motor compensation torque T2 is set; and the electric trailer VCU controls the output motor braking torque TM_rq as TM_rq=T2.

[0015] 3) When the vehicle speed obtained by the electric trailer VCU satisfies Velocity<Vm, it is determined that the low-speed working condition is met. Under the low-speed working condition, if Acc>b and the duration is longer than t3 and the vehicle acceleration Vech_a<a3, the drive assist mode is entered, the electric trailer VCU obtains the coefficient k according to the accelerator pedal opening degree and the vehicle speed interpolation coefficient table table2, and calculates the output motor braking torque TM_rq as TM_rq=k*Torque_max; if Acc>b and the duration is longer than t3 and the vehicle acceleration Vech_a<a3, the motor compensation torque T3 is set; and the electric trailer VCU controls the output motor braking torque TM_rq as TM_rq=T3.

[0016] Preferably, the motor compensation torques T1, T2 and T3 can be obtained according to the motor parameters and tests, and T1>T2>T3.

[0017] More preferably, T1 and T2 are the assist positive torques, such as T1=8N, T2=4N, and the torque of T3 is 0.

[0018] From the above description of the structure of the application, compared with the prior art, the application has the following advantages:

[0019] The trailer VCU of the application obtains the driving behavior of the driver by acquiring the accelerator pedal opening degree signal parameter Acc, the brake pedal opening degree signal parameter Bsk, the signal of the gear panel of the towing vehicle, the hand brake signal and the vehicle speed signal parameter Velocity and the like through can communication, and determines whether the electric trailer needs large power according to different vehicle speed intervals and driving behaviors. If it needs, the brake mode or the drive assist mode is entered, the output motor braking torque is calculated, if it does not need, different motor compensation torques are set according to different vehicle speed intervals, the motor compensation torque is controlled, so that the electric trailer motor is prevented from being dragged to idle and generate a large amount of weak magnetic current during the vehicle running, the power loss generated by the weak magnetic current under the running working condition is effectively reduced, the energy consumption of the whole vehicle is optimized, and the economy of the whole vehicle is improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 This is a control logic schematic diagram of the present invention. DETAILED DESCRIPTION

[0021] The specific implementation of the embodiment of the present invention is described below with reference to the accompanying drawings.

[0022] Reference Figure 1 A method for optimizing energy consumption of a new energy electric trailer integrates an electric drive axle, an all-in-one, power battery, a power battery BMS, a trailer VCU, a battery water cooling unit, a motor cooling system and other components on the electric trailer. Its specific circuit structure is basically the same as that of the transmission electric trailer, so it will not be repeated here.

[0023] Reference Figure 1 In the present invention, the electric trailer VCU communicates with the tractor VCU via CAN. The electric trailer VCU obtains the accelerator pedal opening signal parameter Acc, the brake pedal opening signal parameter Bsk, the tractor gear panel signal, the handbrake signal, and the vehicle speed signal parameter Velocity from the tractor VCU, and uses them to judge the driver's driving behavior and optimize energy consumption based on the driving behavior. The specific steps are as follows:

[0024] Step 1: The electric trailer is powered on and the vehicle enters GO mode.

[0025] Step 2: In the vehicle GO mode, determine whether the handbrake signal is 0. If the handbrake is released, the handbrake signal = 0. At the same time, determine whether the driver is in D gear, that is, whether the tractor gear panel signal is 1. If the tractor gear panel signal = 1, that is, the handbrake is released and the driver is in D gear, the vehicle enters the driving mode.

[0026] In this embodiment, when the tractor gear panel signal = 1, the tractor gear panel signal is in D gear, that is, the vehicle is in forward gear; when the tractor gear panel signal = 2, the tractor gear panel signal is in N gear, that is, the vehicle is in neutral gear; when the tractor gear panel signal = 3, the tractor gear panel signal is in R gear, that is, the vehicle is in reverse gear.

[0027] Step 3: In vehicle driving mode, when the Bsk obtained by the electric trailer is greater than 0, the vehicle enters braking mode. The electric trailer VCU obtains the coefficient K based on the brake pedal opening and vehicle speed interpolation coefficient table 1. According to the motor model, its current maximum output torque is Torque_max, and the output motor braking torque TM_rq is calculated as: TM_rq=K*Torque_max.

[0028] In this embodiment, the brake pedal opening and vehicle speed interpolation coefficient table table1 is a coefficient table calibrated according to the motor parameters used, engineering experience and test. In addition, the output of the motor braking torque in the braking mode is a negative torque, thereby realizing brake energy recovery.

[0029] Step four, in the whole vehicle driving mode, when the electric trailer Acc>0, the electric trailer enters the driving mode, according to different vehicle speed intervals and the throttle pedal opening signal and the whole vehicle acceleration in the vehicle speed interval, it is judged whether the electric trailer enters the driving assist mode, if it enters the driving assist mode, the output motor braking torque is calculated according to the throttle pedal opening and vehicle speed interpolation coefficient table table2, if it does not enter the driving mode, different motor compensation torques are set according to different vehicle speed intervals, and the motor braking torque controlled by the electric trailer VCU is equal to the set motor compensation torque.

[0030] More specifically, in step four, the vehicle high-speed working condition threshold parameter Vb, the vehicle medium-speed working condition threshold parameter Vm, the high-speed working condition whole vehicle acceleration threshold parameter a1, the medium-speed working condition whole vehicle acceleration threshold parameter a2, the low-speed working condition whole vehicle acceleration threshold parameter a3, the throttle pedal opening calibration threshold parameter b, the calibration high-speed working condition cumulative Acc>b time threshold parameter t1, the calibration medium-speed working condition cumulative Acc>b time threshold parameter t2, and the calibration low-speed working condition cumulative Acc>b time threshold parameter t3 are set.

[0031] Among them, the parameters Vb and Vm are used as vehicle speed thresholds for determining the vehicle speed condition, which can be calibrated according to driving behavior experience, and Vb> Vm. The parameters a1, a2 and a3 are acceleration thresholds calibrated according to vehicle parameters and driving behavior experience. The parameter b is used as a throttle pedal opening calibration threshold, which can be calibrated according to vehicle throttle parameters and driving behavior test. The parameters t1, t2 and t3 are time thresholds which can be calibrated through driving behavior experience.

[0032] Reference Figure 1 After the parameter setting is completed, the electric trailer VCU calculates different motor braking torques or field weakening current compensation torques according to different vehicle speed intervals, and the specific steps are as follows:

[0033] 1) When the vehicle speed obtained by the electric trailer VCU satisfies Velocity > Vb, it is determined as high-speed working condition. Under high-speed working condition, if it satisfies Acc > b and the duration > t1 and the vehicle acceleration Vech_a < a1, it enters the drive assist mode. The electric trailer VCU obtains the coefficient k according to the accelerator pedal opening and the vehicle speed interpolation coefficient table table2, and calculates the output motor braking torque TM_rq as: TM_rq = k * Torque_max. If it does not satisfy Acc > b and the duration > t1 and the vehicle acceleration Vech_a < a1, the motor compensation torque T1 is set. The electric trailer VCU controls the output motor braking torque TM_rq as: TM_rq = T1.

[0034] 2) When the vehicle speed obtained by the electric trailer VCU satisfies Vb > Velocity > Vm, it is determined as medium-speed working condition. Under medium-speed working condition, if it satisfies Acc > b and the duration > t2 and the vehicle acceleration Vech_a < a2, it enters the drive assist mode. The electric trailer VCU obtains the coefficient k according to the accelerator pedal opening and the vehicle speed interpolation coefficient table table2, and calculates the output motor braking torque TM_rq as: TM_rq = k * Torque_max. If it does not satisfy Acc > b and the duration > t2 and the vehicle acceleration Vech_a < a2, the motor compensation torque T2 is set. The electric trailer VCU controls the output motor braking torque TM_rq as: TM_rq = T2.

[0035] 3) When the vehicle speed obtained by the electric trailer VCU satisfies Velocity < Vm, it is determined as low-speed working condition. Under low-speed working condition, if it satisfies Acc > b and the duration > t3 and the vehicle acceleration Vech_a < a3, it enters the drive assist mode. The electric trailer VCU obtains the coefficient k according to the accelerator pedal opening and the vehicle speed interpolation coefficient table table2, and calculates the output motor braking torque TM_rq as: TM_rq = k * Torque_max. If it does not satisfy Acc > b and the duration > t3 and the vehicle acceleration Vech_a < a3, the motor compensation torque T3 is set. The electric trailer VCU controls the output motor braking torque TM_rq as: TM_rq = T3.

[0036] Wherein, the above motor compensation torques T1, T2 and T3 can be obtained according to motor parameters and test, and T1 > T2 > T3. In this embodiment, T1 and T2 are assistive positive torques, such as T1 = 8N, T2 = 4N, and the torque of T3 is 0.

[0037] The setting of the motor compensation torques T1, T2 and T3 is because, in the high-speed working condition and the medium-speed working condition, if the electric trailer does not meet the condition of large power demand, at this time, the motor output torque of the traditional electric trailer is 0, that is, the motor of the transmission trailer does not need to participate in the power assistance, but because in the high-speed working condition and the medium-speed working condition, the trailer motor is dragged to idle, which will generate a large weak magnetic current and cause the capacity loss, therefore, the trailer VCU outputs a power assistance positive torque T1 and T2 to the trailer motor as the motor compensation torque, the value is usually small, which can effectively avoid the power consumption loss caused by the motor idling. And, in the low-speed working condition, the speed of the trailer motor dragged to idle is relatively slow, and the weak magnetic current caused thereby is extremely small, so the motor compensation torque T3 in the low-speed working condition can be set to 0.

[0038] The above is only a specific embodiment of the present application, but the design concept of the present application is not limited thereto, and any non-essential modification of the present application using the concept shall be regarded as an infringement of the protection scope of the present application.

Claims

1. A method for optimizing energy consumption of a new energy electric trailer, characterized by: The electric trailer VCU communicates with the tractor VCU through CAN. The electric trailer VCU obtains the accelerator pedal opening signal parameter Acc, brake pedal opening signal parameter Bsk, tractor gear panel signal, parking brake signal, and vehicle speed signal parameter Velocity from the tractor VCU. The specific steps for optimizing the energy consumption of the electric trailer are as follows: Step 1: The electric trailer is powered on and enters GO mode; Step 2: In the vehicle GO mode, the parking brake signal and the tractor gear panel signal are judged. If the parking brake signal = 0 at the same time, that is, the parking brake is released and the tractor gear panel signal is in the forward gear, the vehicle enters the driving mode; Step 3: In vehicle driving mode, when the Bsk obtained by the electric trailer is greater than 0, the vehicle enters braking mode. The electric trailer VCU obtains the coefficient K based on the brake pedal opening and vehicle speed interpolation coefficient table 1. According to the motor model, the current maximum output torque is Torque_max. The output motor braking torque TM_rq is calculated as: TM_rq=K*Torque_max; Step 4: In the vehicle driving mode, when the electric trailer Acc>0, the electric trailer enters the driving mode. According to different vehicle speed ranges and the accelerator pedal opening signal and vehicle acceleration within the speed range, it is determined whether the electric trailer enters the driving assist mode. If it enters the driving assist mode, the output motor braking torque is calculated according to the accelerator pedal opening and vehicle speed interpolation coefficient table 2. If it does not enter the driving mode, different motor compensation torques are set according to different vehicle speed ranges. The motor braking torque output by the electric trailer VCU control is equal to the set motor compensation torque.

2. The method for optimizing energy consumption of a new energy electric trailer according to claim 1, characterized in that: The tractor gear panel signal includes forward gear, reverse gear and neutral gear.

3. The method for optimizing energy consumption of a new energy electric trailer according to claim 1, characterized in that: In the step 4, the vehicle high-speed working condition threshold parameter Vb, the vehicle medium-speed working condition threshold parameter Vm, the high-speed working condition vehicle acceleration threshold parameter a1, the medium-speed working condition vehicle acceleration threshold parameter a2, the low-speed working condition vehicle acceleration threshold parameter a3, the accelerator pedal opening calibration threshold parameter b, the calibration high-speed working condition cumulative Acc>b time threshold parameter t1, the calibration medium-speed working condition cumulative Acc>b time threshold parameter t2, the calibration low-speed working condition cumulative Acc>b time threshold parameter t3 are set, and different motor braking torques or weak magnetic current compensation torques are calculated and output according to different vehicle speed ranges. The specific steps are as follows: 1) When the vehicle speed obtained by the electric trailer VCU satisfies Velocity>Vb, it is determined to be a high-speed operating condition. Under the high-speed operating condition, if Acc>b and the duration is>t1 and the vehicle acceleration Vech_a<a1, the electric trailer enters the driving assist mode. The electric trailer VCU obtains the coefficient k based on the accelerator pedal opening and the vehicle speed interpolation coefficient table table2, and calculates the output motor braking torque TM_rq as: TM_rq=k*Torque_max; if Acc>b is not satisfied and the duration is>t1 and the vehicle acceleration Vech_a<a1, the motor compensation torque T1 is set; the electric trailer VCU controls the output motor braking torque TM_rq as: TM_rq=T1; 2) When the vehicle speed obtained by the electric trailer VCU satisfies Vb>Velocity>Vm, it is determined to be a medium-speed operating condition. Under the medium-speed operating condition, if Acc>b and the duration is>t2 and the vehicle acceleration Vech_a<a2, the electric trailer enters the driving assist mode. The electric trailer VCU obtains the coefficient k based on the accelerator pedal opening and the vehicle speed interpolation coefficient table table2, and calculates the output motor braking torque TM_rq as: TM_rq=k*Torque_max; if Acc>b and the duration is>t2 and the vehicle acceleration Vech_a<a2 are not satisfied, the motor compensation torque T2 is set; the electric trailer VCU controls the output motor braking torque TM_rq as: TM_rq=T2; 3) When the vehicle speed obtained by the electric trailer VCU satisfies Velocity<Vm, it is determined to be a low-speed operating condition. Under the low-speed operating condition, if Acc>b and the duration is>t3 and the vehicle acceleration Vech_a<a3, the drive assist mode is entered. The electric trailer VCU obtains the coefficient k based on the accelerator pedal opening and the vehicle speed interpolation coefficient table table2, and calculates the output motor braking torque TM_rq as: TM_rq=k*Torque_max; if Acc>b is not satisfied and the duration is>t3 and the vehicle acceleration Vech_a<a3, the motor compensation torque T3 is set; the electric trailer VCU controls the output motor braking torque TM_rq as: TM_rq=T3.

4. The method for optimizing energy consumption of a new energy electric trailer according to claim 3, characterized in that: The motor compensation torques T1 and T2 are positive torques, and T1>T2>T3.

5. The method for optimizing energy consumption of a new energy electric trailer according to claim 4, characterized in that: The motor compensation torque T3=0.

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