KR102527810B1 - Method and control device for operating an electric vehicle or a hybrid vehicle - Google Patents

Abstract

The present invention relates to a method and control device for driving an electric vehicle or hybrid vehicle having a drive assembly comprising an electric machine, which, when the accelerator pedal is not operating, prevents creep through the electric machine and driving on an incline. Through the function, the actual torque depending on the target torque (2) required by the creep and ramp driving functions on the control side is provided at the output. In this case, according to the present invention, the amount of change in the acceleration 5 formed in the output section is determined according to the actual torque. Depending on the amount of acceleration fluctuation, the maximum allowable creep and ramp running torque 3 is determined. When the target torque (2) required by the creep and ramp driving function is smaller than the maximum allowable creep and ramp driving torque (3), the state in which the target torque (2) required by the creep and ramp driving function does not fluctuate is maintained as When the target torque (2) required by the creep and ramp driving function is greater than the maximum allowable creep and ramp driving torque (3), the target torque (2) required by the creep and ramp driving function is zero or approximately zero. Decrease to 0.

Description

Method and control device for driving an electric vehicle or hybrid vehicle

The present invention relates to a method for driving an electric or hybrid vehicle. The present invention also relates to a control device for driving an electric vehicle or a hybrid vehicle.

When the driver of the electric vehicle or hybrid vehicle operates the accelerator pedal, also referred to as the accelerator, on the driver's side, depending on the driver's pedal operation and thus on the driver's demand, via the electric machine of the electric vehicle or hybrid vehicle, the output unit The actual torque is provided at The actual torque provided, depending on driver demand, can already be monitored via simple safety functions.

Electric and hybrid vehicles with creep and hill driving capabilities are known. Through the creep and ramp driving function, when the accelerator pedal is not operated on the driver's side, the actual torque depending on the target torque required by the creep and ramp driving function on the controller side is provided from the output unit. This allows creep of the vehicle when the vehicle is operated on level ground. Due to this, when the vehicle is operated on an uphill slope, a phenomenon in which the vehicle is pushed backward on the slope is prevented, and preferably creep of the vehicle is also possible on the slope.

When an electric vehicle or a hybrid vehicle uses the creep and slope driving functions as described above, high actual torque may be provided from an output unit through an electric machine. Until now, it has been difficult to monitor the actual torque provided by the output part through the creep and slope driving functions from the control part, because it is usually within the vehicle to measure whether the car is operating on a flat surface or on an uphill slope. This is because there is no technically detectable tilt sensor installed.

However, depending on whether the electric or hybrid vehicle is operated on level ground or on an uphill slope, the same actual torque will cause different effects with respect to vehicle acceleration. Thus, for example, if the vehicle is operated on level ground and an excessively high torque is provided over a too long period of time, undesirable and uncontrolled acceleration of the vehicle may result. This is the downside. Therefore, it is necessary to monitor the reliability or safety of the actual torque provided from the output unit through the creep and slope driving functions.

From DE 10 2015 202 107 A1 a method for eliminating creep torque in hybrid vehicles is known. According to the prior art, a method of applying a creep torque to a wheel of a vehicle and then applying a braking torque to the wheel is proposed. A situation in which the electric machine develops a creep torque as a reaction to a situation where the braking torque exceeds the calibrated threshold is prevented.

Based on this, the object of the present invention is to provide a new type of method and control device for driving an electric or hybrid vehicle.

This problem is solved by a method and control device according to the independent claims. According to the present invention, the amount of acceleration variation formed in the output unit is determined according to the actual torque. Depending on this amount of acceleration fluctuation, the maximum allowable creep and ramp running torque is determined. When the target torque required by the creep and ramp driving function is smaller than the maximum allowable creep and ramp driving torque, the target torque required by the creep and ramp driving function remains unchanged. When the target torque required by the creep and ramp driving function is greater than the maximum allowable creep and ramp driving torque, the target torque required by the creep and ramp driving function is reduced to zero or approximately zero. A control device is configured to carry out the individual steps of the method.

The method and control device according to the present invention provides a simple and reliable method of providing actual torque at the output of an electric or hybrid vehicle with the help of an electric machine (eg a synchronous machine or an asynchronous machine) via creep and ramp driving functions. It enables monitoring from a safety point of view. Due to this, uncontrolled acceleration of the hybrid or electric vehicle can be prevented. Depending on the actual torque, the amount of acceleration change formed in the output part is determined. Depending on the acceleration variation, the maximum allowable creep and ramp running torque is determined. In this case, in order to determine whether the target torque will be maintained without change or reduced to 0 or approximately 0, the target torque required by the control unit is the maximum. compared to the allowable creep and ramp running torque.

According to the present invention, when the target torque required by the creep and ramp driving function is greater than the maximum allowable creep and uphill torque, the target torque required by the creep and ramp driving function is zero in a stepwise or ramped manner. or decrease to approximately zero. In this way, uncontrolled acceleration of the motor vehicle can be prevented reliably and reliably.

According to an improved example, the maximum allowable creep and ramp driving torque is determined in such a way that the maximum allowable creep and ramp driving torque becomes smaller as the acceleration variation formed in the output unit increases. In this way, uncontrolled acceleration of the motor vehicle can be prevented.

According to a preferred improved example, the target torque required by the creep and ramp driving functions is detected in a first time period. Depending on the actual torque, the amount of acceleration change formed in the output unit and the maximum allowable creep and ramp driving torque are determined within a second time period larger than the first time period by an adjustable multiple, and in this case, the maximum allowable The comparison between the creep and ramp running torque and the target torque required by the creep and ramp running function is preferably performed within the second time period. In this way, uncontrolled acceleration of the motor vehicle can be prevented.

According to one preferred improvement, the maximum allowable creep and ramp running torque is determined using the characteristic curve stored in the control unit. Hereby, the maximum permissible creep and ramp running torque can be determined very reliably and simply.

The present invention allows a simple, robust and safe check of the actual torque provided at the output via the electric machine, dependent on the creep and ramp running function, and dependent on the required target torque. The present invention does not require an inclination sensor in the vehicle at all.

Advantageous refinements refer to the dependent claims and the detailed description below. Embodiments of the present invention are described in more detail with reference to the drawings, but are not limited to the above embodiments.
1 is a characteristic curve for carrying out the present invention.
2 is a first time diagram for explaining the present invention.
3 is a second time diagram for explaining the present invention.
4 is a third time diagram for explaining the present invention.

The present invention relates to a method for driving an electric or hybrid vehicle having a drive assembly comprising an electric machine. The invention also relates to a control device for carrying out this method.

The present invention relates to the details of the creep and hill driving function of an electric or hybrid vehicle in which torque is provided at an output via an electric machine.

When the accelerator pedal is not actuated on the driver's side, and preferably even when the brake pedal is not actuated on the driver's side, the actual torque is generated at the output of the vehicle via the creep and hill drive function via the electric machine of the drive assembly. is provided. The actual torque provided by the output part depends on the target torque required by the creep and ramp running function on the control part.

Even when accelerator pedal operation is not performed but brake pedal operation is performed, the required target torque can be calculated by the creep and ramp running function on the control side, or can be output on the control side. When the brake pedal operation is no longer performed or the brake pedal operation is weakened, the target torque required by the controller side is converted into actual torque on the output side by the creep and ramp driving function.

In order to increase the safety of creep and ramp driving functions of an electric vehicle or hybrid vehicle in which actual torque is provided from the output unit through an electric machine, it is proposed to determine the amount of acceleration variation formed at the output unit according to the actual torque according to the present invention. .

The acceleration of the vehicle can be determined from the measured speed of the vehicle, where the acceleration is the first time derivative of the speed. The amount of change in acceleration is the first time derivative of acceleration or the second time derivative of velocity.

Depending on the determined acceleration fluctuation amount, the maximum allowable creep and ramp driving torque are determined. This is preferably carried out through a characteristic map stored on the control side or a characteristic curve stored on the control side. Accordingly, FIG. 1 exemplarily shows the characteristic curve 1 stored in the controller side as described above, in which the maximum allowable creep and ramp running torque M _MAX through the acceleration variation Δa are shown.

When the target torque required by the creep and ramp driving function is smaller than the maximum allowable creep and ramp driving torque determined depending on the amount of acceleration change, the target torque required by the creep and ramp driving function remains unchanged. is maintained, and actual torque is provided from the output unit based on the target torque.

On the other hand, if the target torque required by the control unit by the creep and ramp driving function is greater than the maximum allowable creep and ramp driving torque determined depending on the amount of acceleration change, the target torque required by the creep and ramp driving function decreases to zero or approximately zero. The driving of the drive assembly via the electric machine is then stopped.

The present invention enables a simple and robust safety function for creep and hill driving functions. This function suffices without the need for a sensor system to detect the inclination the vehicle is driven on. Thus, the method according to the invention does not require information about the slope or inclination at which the hybrid or electric vehicle is located.

Further details of the invention are described below with reference to the signal diagrams of FIGS. 2-4 .

2, 3 and 4 show a plurality of time curve profiles 2, 3, 4 and 5 with respect to time t, in other words creep and ramp running by time curve profile 2 The time profile of the target torque required on the control side is shown by the function, and the time profile of the maximum allowable creep and driving torque (M _MAX ) determined depending on the amount of acceleration fluctuation is shown by the time curve profile (3). The time profile of the speed of the electric or hybrid vehicle is shown by the time curve profile (4), and the time profile of the acceleration of the electric or hybrid vehicle is shown by the time curve profile (5). there is.

2 shows curve profiles 2, 3, 4 and 5 for a situation where an electric or hybrid vehicle is standing uphill on a ramp and has to creep. An actual torque is provided at the output by the electric machine of the drive assembly of the electric vehicle or hybrid vehicle, and this actual torque depends on the target torque 2 required on the control side by means of the creep and ramp running functions. The actual torque provided at the output causes the vehicle to travel with an increase in speed in the range of the curved profile 4 and with the formation of an acceleration according to the curved profile 5 . Depending on the determined or formed acceleration variation Δa, through the characteristic curve 1 of FIG. 1, in the case of driving on a ramp in FIG. 2, a constant, maximum allowable creep and ramp running torque (M _MAX or 3) are determined. do. In this case, due to the creep and ramp driving function in FIG. 2 , the target torque 2 required by the control unit always lies below the maximum allowable creep and ramp driving torque 3 . Accordingly, the target torque 2 required by the creep and ramp drive function is permanently smaller than the maximum allowable creep and ramp drive torque 3 . In this case, the target torque 2 is maintained unchanged so as to provide actual torque from the output unit through the electric machine according to the target torque 2 required by the creep and ramp driving functions.

Figure 3 shows curve profiles 2, 3, 4 and 5 for a situation where an electric or hybrid vehicle has to creep on level ground. To this end, in the present embodiment, the target torque 2 is requested from the control unit again by the creep and slope driving functions, and the electric machine of the electric vehicle or hybrid vehicle forms or provides actual torque from the output unit according to the target torque. do. The actual torque induces speed (4) fluctuations and acceleration (5) fluctuations of the vehicle. Depending on the formed acceleration variation, the maximum allowable creep and ramp running torque 3 is determined again through the characteristic curve 1 of FIG. 1 . Also in FIG. 3, the target torque 2 required by the creep and ramp driving function is permanently smaller than the maximum allowable creep and ramp driving torque 3, so that the target torque required by the creep and ramp driving function ( 2) remains unchanged, and actual torque is provided from the output unit according to the target torque.

FIG. 4 illustrates creep and malfunctions of the ramp-going function, which can be detected by the method according to the invention, in particular when a target torque so high that is inherently only permitted for the ramp-going function is required, for example for creeping on level ground. show Fig. 4, as a curved profile 2, clearly shows the target torque required on the control side depending on the creep and ramp running functions. Depending on the target torque (2), the actual torque leading to the speed (4) fluctuations and the acceleration (5) fluctuations at the output section is provided at the output section. Depending on the determined acceleration variation Δa, the maximum allowable creep and ramp running torque 3 is determined again using the characteristic curve 1 of FIG. 1 .

At a time point t1 in FIG. 4 , the target torque 2 required by the creep and ramp driving function becomes greater than the maximum allowable creep and ramp driving torque 3 . This situation is the same at the time point t2 in FIG. 4, that is, by corresponding to the debouncing time Δt (debouncing time) defined after the time point t1, in this case, the creep and slope driving functions demand it. The target torque 2, which becomes, does not remain unchanged, but rather decreases to zero or approximately zero according to the present invention. The expression "approximately zero" means that the target torque may deviate from the specified value of zero.

In FIG. 4 , when the target torque 2 required by the creep and ramp driving function is greater than the maximum allowable creep and ramp driving torque 3, the target torque 2 goes to 0 or approximately 0 in the form of a ramp. decreases to

However, it is also possible to decrease the target torque 2 stepwise.

From the characteristic curve 1 of FIG. 1 stored in the controller side, the larger the acceleration variation Δa formed in the output unit, the smaller the maximum allowable creep and ramp driving torque (3 or M _MAX ) is. Allowable creep and ramp running torques are determined.

In a particularly preferred embodiment of the present invention, the target torque 2 required by the creep and ramp driving functions is detected in a first time period, in particular every 10 ms. Depending on the actual torque, the amount of acceleration change formed in the output section and the maximum allowable creep and ramp running torque 3 depending thereon are determined within a second time period greater than the first time period by an adjustable integer multiple. The second time period is in particular 300 ms. Comparison between the maximum allowable creep and ramp driving torque 3 determined according to the amount of acceleration change and the target torque 2 required by the creep and ramp driving function is performed particularly within the clock of the second time period. That is, when a continuous change in acceleration occurs due to the amount of change in acceleration determined within the second time period, the required target torque 2 is so high that additional torque is no longer formed at the output unit.

The invention also relates to a control device for driving an electric or hybrid vehicle, which control device is used to carry out the method according to the invention.

The control device determines the target torque through the creep and ramp running functions when the accelerator pedal operation is not performed. Also, in the case where no brake pedal operation is performed, the required target torque 2 is converted by the electric machine in order to provide actual torque at the output. The control device determines the amount of acceleration variation formed in the output unit according to the actual torque, and determines the maximum allowable creep and ramp running torque 3 according to the amount of acceleration variation. The control device compares the target torque 2 with the maximum allowable creep and ramp running torque 3 . When the target torque 2 required by the creep and ramp running function is smaller than the maximum allowable creep and hill running torque 3, the control device may not vary the required target torque 2. Alternatively, if the required target torque 2 is greater than the maximum allowable creep and ramp running torque, the control device reduces the required target torque to zero or approximately zero.

The control device is preferably an electronic engine control device for an electric machine. The control device comprises means for carrying out the method according to the invention, i.e. means on the hardware side and means on the software side. To hardware-side means belong the assembly involved in the implementation of the method according to the invention, ie the data interface for exchanging data with, for example, an electrical machine. Also, a processor for data processing and a memory for data storage belong to the hardware-side means. To software-side means, program modules for performing the method according to the present invention belong.

1: characteristic curve
2: profile of required target torque
3: Profile of maximum allowable creep and ramp drive torque
4; speed profile
5: Acceleration profile

Claims (10)

When the accelerator pedal is not operated, through the creep and ramp driving function through the electric machine, the actual torque depending on the target torque (2) required by the creep and ramp driving function on the control side is provided at the output unit, A method for driving an electric or hybrid vehicle having a drive assembly comprising an electric machine, comprising:
The amount of acceleration variation formed in the output unit is determined according to the actual torque,
Depending on the acceleration variation, the maximum allowable creep and ramp driving torque 3 is determined,
When the target torque (2) required by the creep and ramp driving function is smaller than the maximum allowable creep and ramp driving torque (3), the target torque (2) required by the creep and ramp driving function is remain unchanged,
When the target torque (2) required by the creep and ramp driving function is greater than the maximum allowable creep and ramp driving torque (3), the target torque (2) required by the creep and ramp driving function is A method of driving an electric or hybrid vehicle, characterized in that it decreases to zero or approximately zero. The method of claim 1, wherein the target torque required by the creep and ramp driving function is greater than the maximum allowed creep and ramp driving torque (3) when the target torque (2) required by the creep and ramp driving function is greater than the maximum allowable creep and ramp driving torque (3). A driving method of an electric or hybrid vehicle, characterized in that (2) decreases to zero or approximately zero stepwise or in a ramp. The method of claim 1 or 2, wherein the maximum allowable creep and ramp driving torque (3) is determined in such a way that the maximum allowable creep and ramp driving torque becomes smaller as the amount of acceleration variation formed in the output unit increases. Characterized in that, a driving method of an electric vehicle or a hybrid vehicle. 3. A driving method according to claim 1 or 2, characterized in that the maximum allowable creep and ramp running torque (3) is determined using a characteristic curve (1) stored on the controller side. . According to claim 1 or 2,
The target torque 2 required by the creep and ramp driving functions is detected in a first time period,
Characterized in that the amount of acceleration variation formed in the output unit according to the actual torque and the maximum allowable creep and ramp driving torque (3) are determined within a second time period larger than the first time period by an adjustable multiple. , a driving method of an electric or hybrid vehicle. When the accelerator pedal is not operated, the control device requests a target torque (2) from the control side through creep and ramp driving functions, and the electric machine provides actual torque at the output depending on the target torque. A control device for driving an electric vehicle or hybrid vehicle having a drive assembly comprising a machine, comprising:
The control device determines the amount of acceleration variation formed in the output unit according to the actual torque,
The control device determines a maximum allowable creep and ramp driving torque (3) according to the acceleration fluctuation amount,
When the target torque 2 required by the creep and ramp driving function is smaller than the maximum allowable creep and ramp driving torque 3, the control device determines the target torque required by the creep and ramp driving function ( 2) remains unchanged,
When the target torque 2 required by the creep and ramp driving function is greater than the maximum allowable creep and ramp driving torque 3, the control device determines the target torque required by the creep and ramp driving function ( 2) to zero or approximately zero. 7. The electric vehicle or hybrid vehicle according to claim 6, characterized in that the control device determines the maximum allowable creep and hill driving torque (3) using a characteristic curve (1) stored on the control side. control device to drive. 8. The method according to claim 6 or 7, wherein the control device is configured such that the maximum allowable creep and slope driving torque (3) becomes smaller as the amount of acceleration variation formed in the output unit increases, and the maximum allowable creep and A control device for driving an electric or hybrid vehicle, characterized in that it determines the running torque (3) on an incline. The method according to claim 6 or 7, wherein the control device is configured to, when a target torque (2) required by the creep and ramp driving function is greater than a maximum allowable creep and ramp driving torque (3), the creep and ramp driving function. A control device for driving an electric vehicle or a hybrid vehicle, characterized in that it reduces the target torque (2) required by a driving function to zero or approximately zero stepwise or in the form of a ramp. The method according to claim 6 or 7, wherein the control device detects the target torque (2) required by the creep and ramp driving function in a first time period,
The control device determines, within a second time period greater than the first time period by an adjustable multiple, the amount of acceleration variation formed at the output unit and the maximum allowable creep and ramp running torque (3) according to the actual torque. Characterized in that, a control device for driving an electric vehicle or a hybrid vehicle.

Images