阅读说明：本技术 一种纯电动汽车vcu换挡策略 (VCU gear shifting strategy of pure electric vehicle ) 是由 李大明 李少佳 陈建业 汤浩之 于 2020-06-11 设计创作，主要内容包括：本发明提供一种纯电动汽车VCU换挡策略,包括以下步骤：步骤S1：默认情况下,车辆处于无换挡请求状态,即整车停止状态；步骤S2：整车控制器VCU判断是否接收到换挡请求,若接收到换挡请求,则请求电机扭矩清0；步骤S3：当扭矩为0时,判断司机是否挂入空档,当判断为是之后,进行转速调节,转速调主要分两个部分：目标转速计算和目标转速调速；步骤S4：当转速调到目标转速时,控制仪表“提示换挡”指示灯点亮,提示司机进行换挡；步骤S5：驾驶员换挡完成后,控制仪表“提示换挡”指示灯熄灭,完成全部升降档控制。本发明复用传统燃油车变速箱,匹配纯电动汽车的换挡功能,降低纯电动汽车变速箱改装成本,推动新能源汽车行业转型,创造大量经济效益。(The invention provides a VCU gear shifting strategy of a pure electric vehicle, which comprises the following steps: step S1: under the default condition, the vehicle is in a state without gear shifting request, namely the whole vehicle is in a stop state; step S2: the VCU of the vehicle control unit judges whether a gear shifting request is received, and if the gear shifting request is received, the VCU requests the torque of the motor to be clear 0; step S3: when the torque is 0, judging whether a driver is in neutral or not, and after the judgment is yes, carrying out rotation speed regulation which mainly comprises two parts: calculating a target rotating speed and regulating the target rotating speed; step S4: when the rotating speed is adjusted to the target rotating speed, a 'gear shifting prompting' indicator lamp of the control instrument is lightened to prompt a driver to shift gears; step S5: after the driver finishes shifting, the control instrument 'prompting shifting' indicator lamp is turned off to finish all lifting gear control. The invention reuses the traditional fuel vehicle gearbox, matches the gear shifting function of the pure electric vehicle, reduces the refitting cost of the pure electric vehicle gearbox, promotes the transformation of the new energy vehicle industry and creates a great deal of economic benefit.)

1. A VCU gear-shifting strategy of a pure electric vehicle is characterized by comprising the following steps of S1: under the default condition, the vehicle is in a state without gear shifting request, namely the whole vehicle is in a stop state;

step S2: the VCU of the vehicle control unit judges whether a gear shifting request is received, and if the gear shifting request is received, the VCU requests the torque of the motor to be clear 0;

step S3: when the torque is 0, judging whether a driver is in neutral or not, and after the judgment is yes, carrying out rotation speed regulation which mainly comprises two parts: calculating a target rotating speed and regulating the target rotating speed;

step S4: when the rotating speed is adjusted to the target rotating speed, a 'gear shifting prompting' indicator lamp of the control instrument is lightened to prompt a driver to shift gears;

step S5: after the driver finishes shifting gears, the control instrument 'prompt shifting' indicator lamp is turned off to finish all lifting gear control;

step S6: the vehicle returns to the no shift request state once there is a malfunction between step S2 and step S5.

2. The pure electric vehicle VCU shift strategy of claim 1, wherein: the target rotation speed calculation in step S3 is calculated according to the following formula: v is multiplied by I₁×I₂0.377 × r × N, i.e.

3. The pure electric vehicle VCU shift strategy of claim 2, wherein: and step S3, processing and implementing the target rotation speed regulation in the motor controller MCU, sending the calculated target rotation speed to the MCU in the form of a message through a controller area network CAN communication protocol between the vehicle controller VCU and the motor controller MCU, and adjusting the target rotation speed in the MCU.

4. The pure electric vehicle VCU shift strategy of claim 3, wherein: in the shifting process from step S2 to step S5, a fault diagnosis is performed in each state, and if there is a fault, the state is timed out, and the timed-out state returns to the no-shift-request state in any state.

5. The pure electric vehicle VCU shift strategy of claim 3, wherein: the VCU of the vehicle control unit acquires driver demand input and current vehicle state information, wherein the driver demand input and the current vehicle state information comprise accelerator pedal opening, brake pedal opening, a hand brake switch, a current gear state and current actual vehicle speed information.

6. The pure electric vehicle VCU shift strategy of claim 5, wherein: the whole vehicle state before and after the driver shifts gears comprises a whole vehicle stop state, a whole vehicle parking state, a whole vehicle reverse gear state and a whole vehicle forward state.

7. The pure electric vehicle VCU shift strategy of claim 6, wherein: the entering of the parking state of the whole vehicle needs to meet the following requirements: the driver shifts the gear lever to the P gear;

the condition that the vehicle is out of the parking state and jumps to the vehicle parking state is met: the gear lever exits the gear P;

the reverse gear state of the whole vehicle needs to be met: the N gear is not engaged, the hand brake is not tensioned by a driver, the brake is not stepped, and the whole vehicle is kept in a stop state if the hand brake is not stepped;

the condition that the vehicle is shifted out of the reverse gear state of the whole vehicle and is shifted into the vehicle stop state is met: the current speed is 0, the accelerator pedal is not stepped, and if the current speed is not 0, the vehicle backing state is maintained;

the condition that the vehicle is out of the stopping state and jumps to the advancing state of the whole vehicle is met: the driver shifts the gear lever to the D gear without engaging the N gear or the R gear, the driver does not tighten the hand brake, the brake is not stepped, and if the gear lever is not in the D gear or the R gear, the vehicle is kept in a stop state;

the condition that the vehicle is out of the advancing state and jumps to the stopping state of the vehicle is met: the current speed is 0, the accelerator pedal is not stepped, and if the current speed is not 0, the whole vehicle is in a forward state.

Technical Field

The invention mainly relates to the field of automotive electronics, in particular to a VCU gear shifting strategy of a pure electric vehicle.

Background

Due to the worldwide shortage of petroleum, the development of new energy is a research topic which is widely concerned in the future. The research and development and application of new energy can directly influence the future fate of the automobile industry, and the production of new energy products in the first place becomes the great industry which benefits the current generation and works in the thousand years.

Therefore, the development of new energy automobiles becomes a necessary choice for the development of automobiles in the world. Due to the continuous surge of petroleum price, the new energy automobile shows the advantage of low use cost, and various automobile manufacturers also see the development space of the new energy automobile, and begin to increase the research, development and popularization strength.

The pure electric vehicle has the advantages of mature motor control technology, zero emission, zero pollution, low electric energy cost and the like, and has the dominance in the market share of new energy vehicles. In order to facilitate popularization and use of electric vehicles and efficient operation of motor performance, a gearbox system is often added to control rotation direction and rotation speed adjustment of the motor.

Considering the mechanical structure of the traditional fuel oil automobile and the pure electric automobile, a great amount of differences exist in control mechanisms, so that a plurality of vehicle enterprises are caused, and the problems of difficult modification technology and high cost exist in the industrial transformation from the traditional fuel oil automobile development and production to the electric automobile development and production in the whole vehicle factory.

The published Chinese invention patent, application number CN201710248410.1, patent name: a gear shifting control method for a multi-gear electric wheel drive vehicle is disclosed on the application date: 2017-04-14, the invention relates to a gear shifting control method for a multi-gear electric wheel drive vehicle; the method comprises the following steps: for an n-axis vehicle driven by a multi-gear electric wheel, when a control algorithm judges that gear shifting is needed according to the running state of the vehicle and the operation of a driver, firstly, gear shifting instructions are sent to electric wheels on two sides of a 1 st axis, and the required torque of the whole vehicle is redistributed among the electric wheels of the 2 nd to the n th axes in the gear shifting process of the electric wheels of the 1 st axis; after the electric wheel of the 1 st shaft finishes shifting, the same shifting operation is carried out on the electric wheel of the 2 nd shaft; and repeating the processes in sequence until all the electric wheels on the n axles complete gear shifting. The gear shifting control method can ensure the coordinated gear shifting of each wheel of a multi-gear electric vehicle wheel-driven vehicle in the driving process, effectively relieve the power interruption condition of the vehicle in the gear shifting process and ensure the smoothness of the gear shifting.

Disclosure of Invention

The invention provides a VCU gear shifting strategy of a pure electric vehicle, aiming at the defects in the prior art, and the VCU gear shifting strategy of the pure electric vehicle comprises the following steps:

step S1: under the default condition, the vehicle is in a state without gear shifting request, namely the whole vehicle is in a stop state;

step S2: the VCU of the vehicle control unit judges whether a gear shifting request is received, and if the gear shifting request is received, the VCU requests the torque of the motor to be clear 0;

step S3: when the torque is 0, judging whether a driver is in neutral or not, and after the judgment is yes, carrying out rotation speed regulation which mainly comprises two parts: calculating a target rotating speed and regulating the target rotating speed;

step S4: when the rotating speed is adjusted to the target rotating speed, a 'gear shifting prompting' indicator lamp of the control instrument is lightened to prompt a driver to shift gears;

step S5: after the driver finishes shifting gears, the control instrument 'prompt shifting' indicator lamp is turned off to finish all lifting gear control;

step S6: the vehicle returns to the no shift request state once there is a malfunction between step S2 and step S5.

In this embodiment, the target rotation speed calculation in step S3 is preferably calculated according to the following formula: v is multiplied by I₁×I₂0.377 × r × N, i.e.

Preferably, in this implementation, the target rotation speed is adjusted in step S3 by processing in the MCU, and the calculated target rotation speed is sent to the MCU in the form of a message through a controller area network CAN communication protocol between the VCU of the vehicle controller and the MCU, and the target rotation speed is adjusted in the MCU.

In this embodiment, preferably, during the shifting process from step S2 to step S5, a fault diagnosis is performed in each state, and if there is a fault, the state is timed out, and the timed-out state returns to the no-shift-request state in any state.

Preferably, in this implementation, the vehicle control unit VCU obtains the driver demand input and the current vehicle state information, including the accelerator pedal opening, the brake pedal opening, the hand brake switch, the current gear state, and the current actual vehicle speed information.

In the implementation, the vehicle state before and after the driver shifts gears preferably comprises a vehicle stopping state, a vehicle parking state, a vehicle reverse gear state and a vehicle advancing state.

Preferably, in this implementation, entering the parking state of the whole vehicle needs to satisfy: the driver shifts the gear lever to the P gear;

the condition that the vehicle is out of the parking state and jumps to the vehicle parking state is met: the gear lever exits the gear P;

the reverse gear state of the whole vehicle needs to be met: the N gear is not engaged, the hand brake is not tensioned by a driver, the brake is not stepped, and the whole vehicle is kept in a stop state if the hand brake is not stepped;

the condition that the vehicle is shifted out of the reverse gear state of the whole vehicle and is shifted into the vehicle stop state is met: the current speed is 0, the accelerator pedal is not stepped, and if the current speed is not 0, the vehicle backing state is maintained;

the condition that the vehicle is out of the stopping state and jumps to the advancing state of the whole vehicle is met: the driver shifts the gear lever to the D gear without engaging the N gear or the R gear, the driver does not tighten the hand brake, the brake is not stepped, and if the gear lever is not in the D gear or the R gear, the vehicle is kept in a stop state;

the condition that the vehicle is out of the advancing state and jumps to the stopping state of the vehicle is met: the current speed is 0, the accelerator pedal is not stepped, and if the current speed is not 0, the whole vehicle is in a forward state.

The invention has the beneficial effects that: the gear shifting function of the pure electric vehicle can be matched by reusing the traditional fuel vehicle gearbox or only modifying a small amount of fuel vehicle gearbox, so that the modification cost of the pure electric vehicle gearbox is reduced, the transformation of the new energy vehicle industry is promoted, and a large amount of economic benefits are created.

Drawings

FIG. 1 is a state jump schematic of a shift strategy of the present invention;

FIG. 2 is a policy flow diagram of the present invention;

Detailed Description

As shown in fig. 1-2, the present invention comprises the following steps:

step S1: under the default condition, the vehicle is in a state without gear shifting request, namely the whole vehicle is in a stop state;

step S2: the VCU of the vehicle control unit judges whether a gear shifting request is received, and if the gear shifting request is received, the VCU requests the torque of the motor to be clear 0;

step S3: when the torque is 0, judging whether a driver is in neutral or not, and after the judgment is yes, carrying out rotation speed regulation which mainly comprises two parts: calculating a target rotating speed and regulating the target rotating speed;

step S4: when the rotating speed is adjusted to the target rotating speed, a 'gear shifting prompting' indicator lamp of the control instrument is lightened to prompt a driver to shift gears;

step S5: after the driver finishes shifting gears, the control instrument 'prompt shifting' indicator lamp is turned off to finish all lifting gear control;

step S6: the vehicle returns to the no shift request state once there is a malfunction between step S2 and step S5.

In use, the gear shifting function of the pure electric vehicle can be matched by reusing the traditional fuel vehicle gearbox or only modifying a small amount of the gearbox, so that the modification cost of the pure electric vehicle gearbox is reduced, the transformation of the new energy vehicle industry is promoted, and a large amount of economic benefits are created;

this control strategy stirs gear lever to corresponding gear according to the driver, acquires gear information through the sensor, judges driver's target demand, is in the protection to automobile mechanical parts and to the consideration of driver's security, judges the realization that whether current driving state can satisfy driver's demand, realizes intelligent diagnosis to a certain extent, reduces because potential safety hazard and the durable loss of extra machinery that driver maloperation leads to.

In this embodiment, the target rotation speed calculation in step S3 is preferably calculated according to the following formula: v is multiplied by I₁×I₂0.377 × r × N, i.e.

Where V is the vehicle speed (km/h), r is the tire radius (m), N is the rotational speed (rpm), and the speed ratio and gearbox step ratio. Since the engine speed r is in rpm, the relationship between wheel radius and diameter is 2pi, the vehicle speed is in km/h, and there are several constants in the middle: 2pi, rpm/sec conversion, and m/s to km/h conversion, an approximation of 0.377 was calculated.

Preferably, in this implementation, the target rotation speed is adjusted in step S3 by processing in the MCU, and the calculated target rotation speed is sent to the MCU in the form of a message through a controller area network CAN communication protocol between the VCU of the vehicle controller and the MCU, and the target rotation speed is adjusted in the MCU.

In this embodiment, preferably, during the shifting process from step S2 to step S5, a fault diagnosis is performed in each state, and if there is a fault, the state is timed out, and the timed-out state returns to the no-shift-request state in any state.

Preferably, in this implementation, the vehicle control unit VCU obtains the driver demand input and the current vehicle state information, including the accelerator pedal opening, the brake pedal opening, the hand brake switch, the current gear state, and the current actual vehicle speed information.

In the implementation, the vehicle state before and after the driver shifts gears preferably comprises a vehicle stopping state, a vehicle parking state, a vehicle reverse gear state and a vehicle advancing state.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the method comprises the steps of obtaining driver demand input and current vehicle state information through a whole vehicle sensor, wherein the driver demand input and the current vehicle state information comprise accelerator pedal opening, brake pedal opening, a hand brake switch, a current gear state and current actual vehicle speed information. This control strategy stirs gear lever to corresponding gear according to the driver, acquires gear information through the sensor, judges driver's target demand, is in the protection to automobile mechanical parts and to the consideration of driver's security, judges the realization that whether current driving state can satisfy driver's demand, realizes intelligent diagnosis to a certain extent, reduces because potential safety hazard and the durable loss of extra machinery that driver maloperation leads to.

Fig. 1 is a state jump diagram of a gear shift strategy, wherein when a vehicle control unit is powered on, the vehicle enters a default state, namely a vehicle stop state. And during gear shifting, whether gear shifting is allowed or not is judged according to the gear information and the current driving condition.

If the driver shifts the gear lever to the P gear, directly jumping to a 'parking state of the whole vehicle';

when the gear lever exits from the gear P, the vehicle directly exits from the parking state of the whole vehicle, and jumps to the parking state of the whole vehicle;

if the driver dials the gear lever to the R gear, whether 3 conditions of allowing the vehicle to reverse are met simultaneously needs to be judged: 1. and 2, the driver does not tighten the hand brake, and 3, the brake is not stepped. If any one of the 3 conditions is not met, the vehicle does not enter a vehicle reverse gear state, and the vehicle stop state is continuously kept.

If the vehicle is currently in a vehicle backing state, whether 2 backing conditions of backing off are met simultaneously needs to be judged: 1. the current speed is 0, 2, the accelerator pedal is not pressed. If any one of the 2 conditions is not met, the vehicle does not jump to the vehicle stopping state, and the vehicle reversing state is continuously kept.

If the driver dials the gear lever to the D gear, whether 3 conditions of allowing the vehicle to reverse are met simultaneously needs to be judged: 1. and 2, the driver does not tighten the hand brake, and 3, the brake is not stepped. If any one of the 3 conditions is not met, the vehicle does not enter the vehicle advancing state, and the vehicle stopping state is continuously kept.

If the vehicle is in a vehicle advancing state, whether 2 conditions of backing off the vehicle are met at the same time needs to be judged: 1. the current speed is 0, 2, the accelerator pedal is not pressed. If any one of the 2 conditions is not met, the vehicle does not jump to the vehicle stopping state, and the vehicle advancing state is continuously kept.

The vehicle is in a vehicle advancing state, the vehicle is in a low-gear state and a high-gear state, the two states are changed, namely, the lifting gear control is performed, when the high gear and the low gear are shifted, the motor needs to be adjusted to a proper rotating speed for shifting, and when the vehicle speed is low, the motor is engaged in the low gear or when the vehicle speed is high, the motor is engaged in the high gear.

The above-described embodiments are merely illustrative of the principles and utilities of the present patent application and are not intended to limit the present patent application. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of this patent application. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical concepts disclosed in the present application shall be covered by the claims of this patent application.