CN118055876A

CN118055876A - Acceleration control method and acceleration control device for hybrid vehicle

Info

Publication number: CN118055876A
Application number: CN202180102702.9A
Authority: CN
Inventors: 莫延召
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2024-05-17
Also published as: DE112021008412T5; WO2023070599A1

Abstract

An acceleration control method for a hybrid vehicle specifically includes: identifying whether a torque limitation deficiency condition is satisfied during an increase in a position of an accelerator pedal; when it is recognized that the torque limitation deficiency condition is satisfied, switching the torque limitation of the driving motor from the initial torque limitation to a peak torque limitation calculated from the peak discharge power of the battery; after switching the torque limit of the driving motor to the peak torque limit, identifying whether an exit condition is satisfied; when it is recognized that the exit condition is satisfied, the torque limit of the drive motor is switched from the peak torque limit to a continuous torque limit calculated from the continuous discharge power of the battery. The method improves acceleration response performance of the hybrid vehicle. And also relates to an acceleration control device.

Description

Acceleration control method and acceleration control device for hybrid vehicle

Technical Field

The invention relates to the technical field of vehicles. In particular, the present invention relates to an acceleration control method and an acceleration control device for a hybrid vehicle.

Background

Under the background that the problems of energy and environment are increasingly prominent, new energy vehicles are increasingly receiving attention. A p1+p3 layout hybrid vehicle is a new energy vehicle of the type that is currently in common use, and fig. 1 shows a schematic diagram of a power system of a hybrid vehicle employing such a layout. Wherein, the generator GM is connected with the rear end of the engine E (internal combustion engine, ICE) and the front end of the clutch K0, namely the P1 position; the drive motor DM is connected at the rear end of the transmission, i.e., the P3 position. When the clutch K0 is disengaged, the drive motor DM can directly drive the vehicle, and the generator GM can recover the torque of the engine E to generate electric power. When the clutch K0 is closed, the engine E and the generator GM drive the vehicle together with the drive motor DM via the clutch K0.

Since the p1+p3 layout hybrid vehicle uses the dog clutch, the engine torque must be reduced to zero when switching between the series mode, the parallel mode, and the electric-only mode of the engine E and the drive motor DM, and during this period the engine E cannot provide a power output.

When the vehicle is traveling in the series mode and the driver is rapidly stepping deep on the accelerator in the low or zero accelerator position, the torque response of the engine E is retarded in the initial stage, and the drive motor DM is battery-powered to drive the vehicle. When the actual discharge power of the battery reaches its continuous power limit, it is necessary to wait for the engine E to increase the rotation speed and torque before further supplying energy to the driving motor DM. During the increase of the rotational speed and torque of the engine E, the power supplied by the engine E is very small and cannot meet the needs of the driver. Only after the mode switch and the completion of the engine torque response, the engine E can supply more power to the driving motor DM. Thus, the acceleration performance of the vehicle has two inconsistent phases, making the driving experience poor.

Disclosure of Invention

Accordingly, the present invention has been made to solve the technical problem of providing an acceleration control method that improves acceleration response performance of a hybrid vehicle.

The above technical problem is solved by an acceleration control method for a hybrid vehicle according to the present invention. The hybrid vehicle includes a power system including a generator that introduces the power system between the engine and the clutch, and a drive motor that introduces the power system at the rear end of the transmission, the power system being controlled by an accelerator pedal of the hybrid vehicle, the drive motor being powered by a battery. The acceleration control method comprises the following steps:

identifying whether a torque limitation deficiency condition is satisfied during an increase in a position of an accelerator pedal;

when it is recognized that the torque limitation deficiency condition is satisfied, switching the torque limitation of the driving motor from the initial torque limitation to a peak torque limitation calculated from the peak discharge power of the battery;

after switching the torque limit of the driving motor to the peak torque limit, identifying whether an exit condition is satisfied; and

When it is recognized that the exit condition is satisfied, the torque limit of the drive motor is switched from the peak torque limit to a continuous torque limit calculated from the continuous discharge power of the battery.

According to a preferred embodiment of the present invention, the torque limitation insufficient condition may be that the actual position increase rate of the accelerator pedal is greater than the predetermined position increase rate and the actual position of the accelerator pedal is greater than the predetermined position. An actual position increase rate of the accelerator pedal being larger than the predetermined position increase rate represents that the change of the accelerator position is large, and the change amplitude of the rotating speed and torque values is large; and the actual position of the accelerator pedal is larger than the preset position, which represents that the final value of the accelerator position is large, and the target rotating speed and torque value which are required to be achieved are large.

According to another preferred embodiment of the invention, the predetermined rate of increase and/or the predetermined position may be determined based on the continuous discharge power of the battery and the current response time of the engine.

According to another preferred embodiment of the invention, the exit condition may be that the rotational speed of the engine has reached the target rotational speed and has been maintained for a predetermined time, or that the actual position of the accelerator pedal is less than a predetermined value.

According to another preferred embodiment of the present invention, when it is recognized that the torque limitation insufficient condition is satisfied, the torque limitation of the driving motor may be switched from the initial torque limitation to the peak torque limitation at a first predetermined slope.

According to another preferred embodiment of the present invention, when it is recognized that the exit condition is satisfied, the torque limit of the driving motor may be switched from the peak torque limit to the continuous torque limit at a second predetermined slope.

According to another preferred embodiment of the invention, the initial torque limit may be equal to the continuous torque limit.

According to another preferred embodiment of the present invention, a battery peak torque activation flag may be set, and when it is recognized that a torque limitation deficiency condition is satisfied, the battery peak torque activation flag may be triggered, and the torque limitation of the driving motor may be switched from an initial torque limitation to a peak torque limitation after the battery peak torque activation flag is received; and when it is recognized that the exit condition is satisfied, the battery peak torque activation flag may be reset, and the torque limit of the driving motor may be switched from the peak torque limit to the continuous torque limit after the reset battery peak torque activation flag is received.

According to another preferred embodiment of the present invention, the acceleration control method may be performed by a vehicle controller of a hybrid vehicle.

The above technical problem is also solved by an acceleration control device for a hybrid vehicle according to the present invention. The hybrid vehicle includes a power system including a generator that introduces the power system between the engine and the clutch, and a drive motor that introduces the power system at the rear end of the transmission, the power system being controlled by an accelerator pedal of the hybrid vehicle, the drive motor being powered by a battery. Wherein, this acceleration control device includes:

a start identification module configured to identify whether a torque limitation insufficient condition is satisfied during a position increase of an accelerator pedal;

A first switching module configured to switch a torque limit of the driving motor from an initial torque limit to a peak torque limit calculated from a peak discharge power of the battery when it is recognized that the torque limit insufficiency condition is satisfied;

An exit identifying module configured to identify whether an exit condition is satisfied after switching torque limitation of the driving motor to peak torque limitation; and

And a second switching module configured to switch the torque limit of the driving motor from the peak torque limit to a continuous torque limit calculated from the continuous discharge power of the battery when it is recognized that the exit condition is satisfied.

According to a preferred embodiment of the present invention, the torque limitation insufficient condition may be that an actual position increase rate of the accelerator pedal is greater than a predetermined position increase rate and the actual position of the accelerator pedal is greater than a predetermined position, and the start-up recognition module may include:

a first start-up identifying unit configured to identify whether an actual position increase rate of the accelerator pedal is greater than a predetermined position increase rate; and

And a second start-up recognition unit configured to recognize whether an actual position of the accelerator pedal is greater than a predetermined position.

According to another preferred embodiment of the invention, the start-up identification module may comprise a determination unit configured to determine the predetermined rate of increase and/or the predetermined position based on the continuous discharge power of the battery and the current response time of the engine.

According to another preferred embodiment of the present invention, the exit condition may be that the rotational speed of the engine has reached the target rotational speed and has been maintained for a predetermined time, or that the actual position of the accelerator pedal is less than a predetermined value, and the exit recognition module may include:

a first exit identifying unit configured to identify whether the rotational speed of the engine has reached a target rotational speed and has been held for a predetermined time; and

And a second exit recognition unit configured to recognize whether an actual position of the accelerator pedal is less than a predetermined value.

According to another preferred embodiment of the present invention, the start-up identification module may include a triggering unit configured to trigger the battery peak torque activation flag upon identification that the torque limitation insufficient condition is satisfied; and

The exit identifying module may include a resetting unit configured to reset the battery peak torque activation flag when it is identified that the exit condition is satisfied.

Drawings

The invention is further described below with reference to the accompanying drawings. Like reference numerals in the drawings denote functionally identical elements. Wherein:

FIG. 1 illustrates a schematic diagram of a powertrain to which an acceleration control method according to an exemplary embodiment of the present invention is applied;

FIG. 2 illustrates a flow chart of steps of an acceleration control method according to an exemplary embodiment of the invention; and

Fig. 3a and 3b show response graphs of an acceleration control method according to the related art and an acceleration control method according to an exemplary embodiment of the present invention, respectively.

Detailed Description

Specific embodiments of an acceleration control method and an acceleration control device for a hybrid vehicle according to the present invention will be described below with reference to the accompanying drawings. The following detailed description and the accompanying drawings are provided to illustrate the principles of the invention and not to limit the invention to the preferred embodiments described, the scope of which is defined by the claims.

According to an embodiment of the present invention, there is provided an acceleration control method for a hybrid vehicle. Fig. 1 shows a schematic diagram of a power system of the hybrid vehicle. As shown in fig. 1, the power system includes an engine E, a generator GM, a clutch K0, a transmission T, a differential D, a drive motor DM, a battery (not shown), wheels W, and the like. The generator GM is introduced into the power system at a position P1 between the engine E and the clutch K0, and the generator GM can recover kinetic energy of the engine E to generate electric power and can supply the generated electric power to the battery. The battery is able to power the driving motor DM. The drive motor DM is incorporated into the power train at the P3 position at the rear end of the transmission and is capable of directly driving the wheels W. The powertrain is controlled by an accelerator pedal (not shown) of the hybrid vehicle.

In order to solve the problem of the second-order acceleration of the vehicle when the accelerator is stepped on deeply at a low accelerator position or a zero accelerator position, the following method is used to control the acceleration process of the hybrid vehicle.

As shown in the step diagram of fig. 2, first, in step S1, a trigger condition is identified. Specifically, it is identified whether the torque limitation deficiency condition is satisfied during the increase in the position of the accelerator pedal.

The torque limitation insufficient condition here refers to a case where the current torque limitation (i.e., the maximum torque value that can be reached) of the drive motor DM is insufficient to stably increase the output rotation speed and torque in a state where the clutch K0 is disengaged and the torque response of the engine E is retarded. This situation is generated by the operation of the driver's rapid deep depression of the accelerator pedal. Therefore, determining whether the torque limitation deficiency condition is satisfied needs to be based on two criteria, that is, the speed at which the driver depresses the accelerator pedal and the position at which the accelerator pedal reaches. The speed at which the driver depresses the accelerator pedal may be represented by the rate of increase in the position of the accelerator pedal. Thus, the torque limitation insufficient condition may preferably be that the actual position increase rate of the accelerator pedal is greater than the predetermined position increase rate and the actual position of the accelerator pedal is greater than the predetermined position. When the sensor on the accelerator pedal detects that the actual position increasing rate and the actual position of the accelerator pedal simultaneously exceed the preset values, the condition that the torque limitation is insufficient can be judged to be met, and then a battery peak torque activating mark is triggered to start the next control step; if either the actual position increase rate of the accelerator pedal or the actual position does not exceed the corresponding predetermined value, meaning that the torque limitation insufficient condition is not satisfied, the battery peak torque activation flag is not triggered to start a control step. The predetermined rate of increase and/or the predetermined position may be determined based on the continuous discharge power of the battery and the current response time of the engine E.

If the result of the identification in step S1 is affirmative, that is, the torque limitation insufficient condition is satisfied, the control method will start step S2. In step S2, torque of the switching drive motor DM is limited. Specifically, the torque limit of the drive motor DM is switched from the initial torque limit to the peak torque limit calculated from the peak discharge power of the battery.

The initiation of step S2 may be based on a battery peak torque activation flag. Specifically, a battery peak torque activation flag may be set, triggered when a torque limitation deficiency condition is satisfied, and the above-described switching process is performed after the battery peak torque activation flag is received. The battery peak torque activation flag here is a flag that controls the switching state of the torque limit of the drive motor DM. The battery peak torque activation flag typically has both a triggered and a non-triggered state, corresponding to a peak torque limit calculated from the peak discharge power of the battery and a continuous torque limit calculated from the continuous discharge power of the battery, respectively. This is because the drive motor DM is typically operated under continuous torque limitations. That is, the initial torque limit of the driving motor DM is generally equal to the continuous torque limit calculated from the continuous discharging power of the battery before the starting step S2.

Fig. 3a and 3b show response graphs of a control method according to the prior art and a control method according to an embodiment of the invention, respectively. The torque limit of the driving motor DM is determined by the discharge of the battery, and thus the variation of the torque limit of the driving motor DM can be intuitively reflected by the battery discharge power curves in fig. 3a and 3 b. In step S2, the torque limit of the driving motor DM is switched from the initial torque limit to the peak torque limit, preferably with a certain constant slope. The constant slope may be referred to as a first predetermined slope. This is reflected in fig. 3b as the actual discharge power of the battery rises with a certain constant slope. This allows the torque-limited switching process to be performed stably.

The drive motor DM does not always operate under peak torque limitation, which is only used for a transient period in which the engine E cannot normally output torque during rapid deep depression of the accelerator pedal. Therefore, after the end of the above-described phase, it is necessary to exit the operating state in step S2. For this purpose, an exit condition is identified in step S3. Specifically, after switching the torque limit of the drive motor DM to the peak torque limit, it is identified whether the exit condition is satisfied.

Preferably, the exit condition is that the rotational speed of the engine E has reached the target rotational speed and has been maintained for a predetermined time, or that the actual position of the accelerator pedal is less than a predetermined value. If the rotational speed of the engine E has reached the target rotational speed and has been maintained for a predetermined time, the clutch K0 may be turned on so that the driving may be provided by the engine E, and thus it may not be necessary to continue to rely solely on the driving motor DM to provide the driving force. If the actual position of the accelerator pedal is less than the predetermined value, it is indicated that the actually required output torque becomes small, and the drive motor DM can provide a sufficient driving force without maintaining the peak torque limit.

If the result of the identification in step S3 is affirmative, that is to say an exit condition is fulfilled, the control method will initiate the next step S4. In step S4, the operating state will be exited. Specifically, the torque limit of the driving motor DM is switched again, and the torque limit of the driving motor DM is switched from the peak torque limit to the continuous torque limit calculated from the continuous discharge power of the battery.

Similar to step S2, the exit of step S4 may also be based on the battery peak torque activation flag. Specifically, the battery peak torque activation flag may be reset when the exit condition is satisfied such that the battery peak torque activation flag is reset to a non-trigger state, and the above-described switching process is performed after the reset battery peak torque activation flag is received such that the torque limit of the driving motor DM no longer maintains the peak torque limit.

In order that the switching process of the torque limit may be performed stably, it is preferable to switch the torque limit of the driving motor DM from the peak torque limit to the continuous torque limit with a certain constant slope, similarly to in step S2. The constant slope may be referred to as a second predetermined slope. This is reflected in fig. 3b as the actual discharge power of the battery drops with a certain constant slope.

The acceleration control method described above may be performed by a vehicle controller of a hybrid vehicle. Various data required for executing the control method can be obtained by various sensors inherent in the hybrid vehicle, and therefore no additional components are required.

According to an embodiment of the present invention, there is also provided an acceleration control apparatus for a hybrid vehicle. The acceleration control device may correspondingly perform the acceleration control method described above, and is also applied to the power system of the hybrid vehicle shown in fig. 1. The acceleration control device may be constituted by a functional module in the vehicle control unit. The acceleration control device comprises a starting identification module, a first switching module, an exiting identification module and a second switching module.

The start-up identification module is configured to perform step S1, which is configured to identify whether a torque limitation insufficient condition is satisfied during an increase in the position of the accelerator pedal. Preferably, the start-up recognition module may include a first start-up recognition unit configured to recognize whether an actual position increase rate of the accelerator pedal is greater than a predetermined position increase rate, and a second start-up recognition unit configured to recognize whether the actual position of the accelerator pedal is greater than the predetermined position. Preferably, the start-up identification module may further comprise a determination unit configured to determine the predetermined rate of increase and/or the predetermined position based on the continuous discharge power of the battery and the current response time of the engine E. In addition, the start-up identification module may preferably further include a triggering unit configured to trigger the battery peak torque activation flag when it is identified that the torque limitation insufficient condition is satisfied.

The first switching module is configured to perform step S2 of switching the torque limit of the driving motor DM from the initial torque limit to a peak torque limit calculated from the peak discharge power of the battery upon recognizing that the torque limit deficiency condition is satisfied.

The exit identifying module is configured to identify whether an exit condition is satisfied after switching the torque limit of the driving motor DM to the peak torque limit, for executing step S3. Preferably, the exit recognition module may include a first exit recognition unit configured to recognize whether the rotational speed of the engine E has reached the target rotational speed and has been maintained for a predetermined time, and a second exit recognition unit configured to recognize whether the actual position of the accelerator pedal is less than a predetermined value. In addition, the exit recognition module may further preferably include a reset unit configured to reset the battery peak torque activation flag when it is recognized that the exit condition is satisfied.

The second switching module is configured to perform step S4 of switching the torque limit of the driving motor DM from the peak torque limit to the continuous torque limit calculated from the continuous discharge power of the battery upon recognizing that the exit condition is satisfied.

The acceleration control method and the acceleration control device according to the present invention combine continuous battery power and peak power. As can be seen by comparing the prior art response curve of fig. 3a with the inventive response curve of fig. 3b, the present method and apparatus can compensate for transient power output using peak discharge power of a battery during a period in which torque and rotation speed of an engine are increased in case that a driver rapidly deeply steps on an accelerator pedal, improve the second order acceleration characteristic of a vehicle and the problem of engine response lag, thereby smoothing the power response of the vehicle in time and improving driving comfort.

While possible embodiments are exemplarily described in the above description, it should be understood that there are numerous variations of the embodiments still through all known and furthermore easily conceivable combinations of technical features and embodiments by the skilled person. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. The technical teaching for converting at least one exemplary embodiment is provided more in the foregoing description to the skilled person, wherein various changes may be made without departing from the scope of the claims, in particular with regard to the function and structure of the components.

Reference numeral table

E engine

K0 Clutch device

D differential mechanism

DM driving motor

GM generator

T-shaped speed changer

W wheel

Claims

An acceleration control method for a hybrid vehicle comprising a power system including a Generator (GM) introducing the power system between an engine (E) and a clutch (K0) and a Drive Motor (DM) introducing the power system at the rear end of a transmission (T), the power system being controlled by an accelerator pedal of the hybrid vehicle, the Drive Motor (DM) being battery-powered,

The acceleration control method includes the steps of:

Identifying whether a torque limitation deficiency condition is satisfied during an increase in the position of the accelerator pedal;

Switching a torque limit of the Driving Motor (DM) from an initial torque limit to a peak torque limit calculated from a peak discharge power of the battery when it is recognized that the torque limit insufficiency condition is satisfied;

After switching the torque limit of the Driving Motor (DM) to the peak torque limit, identifying whether an exit condition is satisfied; and

When it is recognized that the exit condition is satisfied, a torque limit of the Driving Motor (DM) is switched from the peak torque limit to a continuous torque limit calculated from a continuous discharge power of the battery.
The acceleration control method according to claim 1, characterized in that the torque limitation deficiency condition is that an actual position increase rate of the accelerator pedal is larger than a predetermined position increase rate and the actual position of the accelerator pedal is larger than a predetermined position.
Acceleration control method according to claim 2, characterized in that the predetermined rate of increase and/or the predetermined position is determined depending on the continuous discharge power of the battery and the current response time of the engine (E).
The acceleration control method according to claim 1, characterized in that the exit condition is that the rotational speed of the engine (E) has reached a target rotational speed and has been held for a predetermined time, or that the actual position of the accelerator pedal is smaller than a predetermined value.
The acceleration control method according to claim 1, characterized in that when it is identified that the torque limitation insufficiency condition is satisfied, the torque limitation of the Drive Motor (DM) is switched from the initial torque limitation to the peak torque limitation with a first predetermined slope.
The acceleration control method according to claim 1, characterized in that when it is recognized that the exit condition is satisfied, the torque limit of the Drive Motor (DM) is switched from the peak torque limit to the continuous torque limit with a second predetermined slope.
The acceleration control method according to claim 1, characterized in, that the initial torque limit is equal to the continuous torque limit.
The acceleration control method according to claim 1, characterized in that a battery peak torque activation flag is set, the battery peak torque activation flag being triggered when it is recognized that the torque limitation deficiency condition is satisfied; and

The battery peak torque activation flag is reset when the exit condition is identified as being met.
The acceleration control method according to any one of claims 1 to 8, characterized in that the acceleration control method is executed by a vehicle controller of the hybrid vehicle.
An acceleration control device for a hybrid vehicle comprising a power system including a Generator (GM) introducing the power system between an engine (E) and a clutch (K0) and a Drive Motor (DM) introducing the power system at the rear end of a transmission (T), the power system being controlled by an accelerator pedal of the hybrid vehicle, the Drive Motor (DM) being battery-powered,

The acceleration control device includes:

A start identification module configured to identify whether a torque limitation insufficient condition is satisfied during a position increase of the accelerator pedal;

A first switching module configured to switch a torque limit of the Driving Motor (DM) from an initial torque limit to a peak torque limit calculated from a peak discharge power of the battery upon recognizing that the torque limit insufficiency condition is satisfied;

An exit identifying module configured to identify whether an exit condition is satisfied after switching a torque limit of the Driving Motor (DM) to the peak torque limit; and

A second switching module configured to switch a torque limit of the Driving Motor (DM) from the peak torque limit to a continuous torque limit calculated from a continuous discharge power of the battery upon recognizing that the exit condition is satisfied.
The acceleration control method according to claim 10, characterized in that the torque limitation deficiency condition is that an actual position increase rate of the accelerator pedal is larger than a predetermined position increase rate and the actual position of the accelerator pedal is larger than a predetermined position, the start-up identifying module includes:

A first activation recognition unit configured to recognize whether an actual position increase rate of the accelerator pedal is greater than the predetermined position increase rate; and

A second activation recognition unit configured to recognize whether an actual position of the accelerator pedal is greater than the predetermined position.
The acceleration control method according to claim 11, characterized in, that the start-up identification module comprises a determination unit configured to determine the predetermined rate of increase and/or the predetermined position depending on the continuous discharge power of the battery and the current response time of the engine (E).
The acceleration control method according to claim 10, characterized in that the exit condition is that the rotational speed of the engine (E) has reached a target rotational speed and has been held for a predetermined time, or that the actual position of the accelerator pedal is smaller than a predetermined value, the exit identifying module includes:

A first exit identifying unit configured to identify whether a rotational speed of the engine (E) has reached the target rotational speed and has been held for the predetermined time; and

And a second exit identifying unit configured to identify whether an actual position of the accelerator pedal is smaller than the predetermined value.
The acceleration control method according to any one of the claims 10-13, characterized in, that the start-up identification module comprises a triggering unit configured to trigger a battery peak torque activation flag upon identifying that the torque limitation insufficient condition is fulfilled; and

The exit recognition module includes a reset unit configured to reset the battery peak torque activation flag when the exit condition is recognized as being satisfied.