CN114559928A - Start-stop control method and system for hybrid electric vehicle - Google Patents

Abstract

The invention provides a hybrid power start-stop control method and a hybrid power start-stop control system, wherein the method comprises the following steps: in the starting process of the engine, calculating compensation torque required by the engine in the starting process according to the power parameter of the engine and the rotating speed change rate of the engine, providing the compensation torque to the engine through a compensation motor, and controlling the engine to stop supplying fuel after reaching the target rotating speed; according to the working condition information of the automobile, the torque of the engine is controlled through the compensation motor, and the engine is controlled to keep a stable rotating speed; during the shutdown process of the engine, controlling the transmitter to be kept at a target rotating speed through the compensating motor so as to enter a shutdown auxiliary mode; and in the stop auxiliary mode, when the engine maintains the target rotating speed for a preset time and does not receive a power request within the preset time, controlling the engine to stop working. The invention can solve the technical problems that the hybrid electric vehicle in the prior art is generally high in noise when the engine is started and stopped and is not beneficial to better NVH realization.

Description

Start-stop control method and system for hybrid electric vehicle

Technical Field

The invention relates to the technical field of automobiles, in particular to a hybrid power start-stop control method and a hybrid power start-stop control system.

Background

At present, automobile consumers pursue higher and higher safety of the automobile, the NVH requirement of the whole automobile is higher and higher nowadays, and the engine is the key NVH optimization direction of each large host computer factory as one of main noise sources in the automobile running process.

At present, a hybrid electric vehicle on the market can basically finish quick starting of an engine mainly by a high-voltage motor, but poor NVH (noise, vibration and harshness) or drivability can be caused by neglecting over-high engine speed or directly spraying oil to the engine in the starting process; another point is that direct withdrawal of motor torque during engine shutdown can cause shock problems.

Therefore, the hybrid electric vehicle in the prior art generally has the technical problems that the noise is large when the engine is started and stopped, and better NVH (noise vibration harshness) is not facilitated.

Disclosure of Invention

Based on the above, the invention aims to provide a method and a system for controlling starting and stopping of a hybrid electric vehicle, and aims to solve the technical problems that the hybrid electric vehicle in the prior art is generally high in noise when an engine starts and stops and is not beneficial to better NVH (noise, vibration and harshness) realization.

One aspect of the present invention provides a start-stop control method for a hybrid vehicle, including:

in the starting process of the engine, calculating compensation torque required by the engine in the starting process according to the power parameter of the engine and the rotating speed change rate of the engine, providing the compensation torque to the engine through a compensation motor, and controlling the engine to stop supplying fuel after reaching a target rotating speed;

according to the working condition information of the automobile, the torque of the engine is controlled through the compensation motor, and the engine is controlled to keep a stable rotating speed;

controlling the transmitter to be kept at a target rotating speed through the compensating motor during the stopping process of the engine so as to enter a stopping auxiliary mode;

and under the stop auxiliary mode, when the engine maintains the target rotating speed for a preset time and does not receive a power request within the preset time, controlling the engine to stop working.

According to one aspect of the above technical solution, the method includes the steps of calculating a compensation torque required by the engine in a starting process according to a preset torque compensation amplitude table and a rotation speed change rate of the engine, providing the compensation torque to the engine through a compensation motor, and controlling the engine to stop supplying fuel after reaching a target rotation speed, and specifically includes:

acquiring an actual rotating speed in the starting process of an engine through a preset rotating speed sensor, and determining the rotating speed change rate of the engine according to the actual rotating speed of the engine;

calculating the compensation torque required by the engine in the starting process according to the power parameter of the engine and the rotating speed change rate;

providing compensation torque for the engine through a preset compensation motor in a hybrid power system according to the calculated compensation torque required by the engine in the starting process;

the engine reaches a preset target rotating speed within a preset time by providing compensation torque to the engine, and the engine is controlled to stop supplying fuel into the cylinder after the engine reaches the target rotating speed.

According to one aspect of the above technical solution, according to the operating condition information of the vehicle, the step of controlling the engine to maintain a stable rotation speed by controlling the torque of the engine through the compensation motor specifically includes:

acquiring working condition information of the automobile, wherein the working condition information at least comprises the current speed of the automobile, the water temperature of an engine and the electric quantity of a battery pack;

according to the working condition information, carrying out torque control on the engine through the compensation motor;

and when the compensation motor controls the torque of the engine, controlling the engine to keep a preset stable rotating speed.

According to one aspect of the above technical solution, the step of controlling the transmitter to maintain a target rotation speed through the compensation motor to enter a shutdown assistance mode specifically includes:

in the stopping process of the engine, recovering the torque force generated in the running process of the engine through the compensating motor to keep the engine at a preset target rotating speed;

controlling the engine to enter a stop assist mode after the engine is maintained at the target speed.

According to an aspect of the foregoing technical solution, the method further includes:

in the stop assist mode, judging whether the engine receives a power request within a preset time when the target rotating speed is maintained;

if not, controlling the engine to stop working.

According to an aspect of the above technical solution, the method further comprises:

and controlling the compensation motor to not provide compensation torque for the engine any more when the water temperature of the engine of the automobile exceeds a preset water temperature threshold value in the next starting process.

According to an aspect of the above-mentioned technical solution,

and when the electric quantity of the battery pack is lower than a preset electric quantity threshold value, controlling the compensation motor to not provide compensation torque for the engine any more.

Another aspect of the present invention is to provide a hybrid vehicle start and stop control system, including:

the starting control module is used for calculating compensation torque required by the engine in the starting process according to a preset torque compensation amplitude table and the rotating speed change rate of the engine in the starting process of the engine, providing the compensation torque to the engine through a compensation motor, and controlling the engine to stop supplying fuel after reaching a target rotating speed;

the starting control module is also used for controlling the torque of the engine through the compensation motor according to the working condition information of the automobile and controlling the engine to keep a stable rotating speed;

the stopping control module is used for controlling the transmitter to be kept at a target rotating speed through the compensation motor so as to enter a stopping auxiliary mode during the stopping process of the engine;

the shutdown control module is further used for controlling the engine to stop working when the engine maintains the target rotating speed for a preset time and does not receive a power request within the preset time in the shutdown auxiliary mode.

According to an aspect of the foregoing technical solution, the start control module is specifically configured to:

acquiring an actual rotating speed in the starting process of an engine through a preset rotating speed sensor, and determining the rotating speed change rate of the engine according to the actual rotating speed of the engine;

calculating the compensation torque required by the engine in the starting process according to the power parameter of the engine and the rotating speed change rate;

providing compensation torque for the engine through a preset compensation motor in a hybrid power system according to the calculated compensation torque required by the engine in the starting process;

the method comprises the steps of enabling the engine to reach a preset target rotating speed within a preset time by providing compensation torque for the engine, and controlling the engine to stop supplying fuel into a cylinder after the engine reaches the target rotating speed.

According to an aspect of the foregoing technical solution, the shutdown control module is specifically configured to:

in the stopping process of the engine, recovering the torque force generated in the running process of the engine through the compensating motor to keep the engine at a preset target rotating speed;

controlling the engine to enter a stop assist mode after the engine is maintained at the target speed.

Compared with the prior art, the start-stop control method and the start-stop control system for the hybrid electric vehicle have the beneficial effects that: during the starting process of the engine, a compensation motor provides compensation torque for the engine and controls the engine to keep a stable rotating speed; during the stopping process of the engine, the engine is controlled to be kept at a target rotating speed through the compensating motor so as to enter a stop auxiliary mode, and when the engine does not receive a power request within a preset time after the target rotating speed is kept for a preset time, the engine is controlled to stop working. The engine shutdown control method and the engine shutdown control device have the advantages that the NVH and the smoothness of the engine startup and shutdown are solved according to different vehicle speeds and working conditions, and meanwhile energy recovery is carried out in the shutdown process so as to achieve rapid shutdown of the engine.

Drawings

FIG. 1 is a flow chart illustrating a method for controlling start and stop of a hybrid electric vehicle according to a first embodiment of the present invention;

FIG. 2 is a block diagram of a control system of a hybrid electric vehicle start-stop system according to a third embodiment of the present invention;

the following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Several embodiments of the invention are presented in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

At present, a hybrid electric vehicle on the market can basically finish quick starting of an engine mainly by a high-voltage motor, but poor NVH (noise, vibration and harshness) or drivability can be caused by neglecting over-high engine speed or directly spraying oil to the engine in the starting process; another point is that direct withdrawal of motor torque during engine shutdown can cause shock problems. In view of the above problems, several embodiments of the present invention mainly provide torque control during start-stop of an engine, thereby solving the above problems.

Example one

Referring to fig. 1, a first embodiment of the present invention provides a start-stop control method for a hybrid vehicle, including steps S10-S40;

specifically, the starting process of the engine mainly includes steps S10-S20, in which:

step S10, in the starting process of the engine, calculating the compensation torque required by the engine in the starting process according to the power parameter of the engine and the rotating speed change rate of the engine, providing the compensation torque to the engine through a compensation motor, and controlling the engine to stop supplying fuel after reaching the target rotating speed;

as is easily understood by those skilled in the art, in the starting process of the engine, the crankshaft of the engine drives the piston to reciprocate under the driving of the starter, and the sound generated during the operation of the engine is loud in a period of time.

Specifically, during the starting process of the engine, the compensation torque required by the engine during the starting process is calculated according to the power parameter of the engine and the rotating speed change rate of the engine, the compensation motor in the hybrid power system is used for providing torque compensation for the engine, so that the rotating speed of the engine can be quickly increased, and when the rotating speed of the engine reaches a preset target rotating speed, the engine is controlled to stop injecting fuel, and at the moment, the sound generated by the operation of the engine can be effectively reduced.

Step S20, according to the working condition information of the automobile, the engine is controlled by the torque of the compensation motor, and the engine is controlled to keep a stable rotating speed;

in some embodiments of the present invention, the operating condition information of the vehicle is mainly operating condition parameters that dominate the power output of the vehicle, including but not limited to the engine water temperature of the vehicle, the battery pack power, and other parameter information.

When the working condition information of the automobile is good, the torque of the engine is controlled through a compensation motor in the hybrid power system, namely, a crankshaft and a piston of the engine are driven to move through the compensation motor, and the compensation motor controls the engine to keep a stable rotating speed.

In the embodiment, the starting strategy of the engine is optimized through the steps S10-S20, so that the sound generated in the cold starting process of the engine can be well reduced, and the NVH level of the automobile is effectively improved.

Specifically, the starting process of the engine mainly includes steps S30-S40, in which:

step S30, controlling the engine to be kept at a target rotating speed through the compensating motor to enter a stop auxiliary mode during the stop process of the engine;

step S40, in the stop assist mode, when the engine maintains the target speed for a preset time and does not receive a power request within the preset time, controlling the engine to stop working.

Steps S30-S40 are primarily engine shutdown strategy optimization, primarily considering energy recovery and shutdown mode jump. The engine is first pulled to a target speed during shutdown, maintained at the target speed for a period of time (shutdown assistance), and the shutdown is completed without a start request.

Compared with the prior art, the control method for starting and stopping the hybrid electric vehicle has the advantages that: during the starting process of the engine, a compensation motor provides compensation torque for the engine and controls the engine to keep a stable rotating speed; during the stopping process of the engine, the engine is controlled to be kept at a target rotating speed through the compensating motor so as to enter a stop auxiliary mode, and when the engine does not receive a power request within a preset time after the target rotating speed is kept for a preset time, the engine is controlled to stop working. The engine shutdown control method and the engine shutdown control device have the advantages that the NVH and the smoothness of the engine startup and shutdown are solved according to different vehicle speeds and working conditions, and meanwhile energy recovery is carried out in the shutdown process so as to achieve rapid shutdown of the engine.

Example two

The second embodiment of the invention provides a method for controlling starting and stopping of a hybrid electric vehicle, which comprises the following steps:

the method comprises the steps of calculating compensation torque required by the engine in the starting process according to a preset torque compensation amplitude table and the rotating speed change rate of the engine, providing the compensation torque to the engine through a compensation motor, and controlling the engine to stop supplying fuel after reaching a target rotating speed, wherein the steps comprise the steps of S11-S14:

step S11, acquiring the actual rotating speed of the engine in the starting process through a preset rotating speed sensor, and determining the rotating speed change rate of the engine according to the actual rotating speed of the engine;

step S12, calculating the compensation torque required by the engine in the starting process according to the power parameter of the engine and the rotating speed change rate;

step S13, according to the calculated compensation torque needed by the engine in the starting process, providing the compensation torque for the engine through a preset compensation motor in the hybrid power system;

and step S14, enabling the engine to reach a preset target rotating speed within a preset time by providing compensation torque to the engine, and controlling the engine to stop supplying fuel into the cylinder after the engine reaches the target rotating speed.

The method comprises the following steps of controlling the engine to keep a stable rotating speed by controlling the torque of the engine through the compensation motor according to the working condition information of the automobile, and specifically comprises the following steps of S21-S23:

step S21, obtaining working condition information of the automobile, wherein the working condition information at least comprises the current speed of the automobile, the water temperature of an engine and the electric quantity of a battery pack;

step S22, according to the working condition information, the torque of the engine is controlled through the compensation motor;

and step S23, controlling the engine to keep a preset stable rotating speed when the compensation motor controls the torque of the engine.

The step of controlling the transmitter to maintain a target rotating speed through the compensation motor to enter the shutdown assistance mode specifically comprises the steps of S31-S32:

step S31, recovering the torque force generated in the running process of the engine through the compensation motor in the stopping process of the engine, and keeping the engine at a preset target rotating speed;

step S32, after the engine is maintained at the target speed, controlling the engine to enter a stop assist mode.

In this embodiment, the method further includes:

in the stop assist mode, judging whether the engine receives a power request within a preset time when the target rotating speed is maintained;

and if not, controlling the engine to stop working.

In this embodiment, the method further includes:

and controlling the compensation motor to not provide compensation torque for the engine any more when the water temperature of the engine of the automobile exceeds a preset water temperature threshold value in the next starting process.

In this embodiment, the method further includes:

and when the electric quantity of the battery pack is lower than a preset electric quantity threshold value, controlling the compensation motor to not provide compensation torque for the engine any more.

Compared with the prior art, the control method for starting and stopping the hybrid electric vehicle has the advantages that: during the starting process of the engine, a compensation motor provides compensation torque for the engine and controls the engine to keep a stable rotating speed; during the stopping process of the engine, the engine is controlled to be kept at a target rotating speed through the compensating motor so as to enter a stop auxiliary mode, and when the engine does not receive a power request within a preset time after the target rotating speed is kept for a preset time, the engine is controlled to stop working. The engine shutdown control method and the engine shutdown control device have the advantages that the NVH and the smoothness of the engine startup and shutdown are solved according to different vehicle speeds and working conditions, and meanwhile energy recovery is carried out in the shutdown process so as to achieve rapid shutdown of the engine.

EXAMPLE III

Referring to fig. 2, a third embodiment of the present invention provides a hybrid vehicle start and stop control system, which includes:

the starting control module 10 is used for calculating compensation torque required by the engine in the starting process according to the power parameter of the engine and the rotating speed change rate of the engine in the starting process of the engine, providing the compensation torque to the engine through a compensation motor, and controlling the engine to stop supplying fuel after reaching a target rotating speed;

as is easily understood by those skilled in the art, in the starting process of the engine, the crankshaft of the engine drives the piston to reciprocate under the driving of the starter, and the sound generated during the operation of the engine is loud in a period of time.

Specifically, during the starting process of the engine, the compensation torque required by the engine during the starting process is calculated according to the power parameter of the engine and the rotating speed change rate of the engine, the compensation motor in the hybrid power system is used for providing torque compensation for the engine, so that the rotating speed of the engine can be quickly increased, and when the rotating speed of the engine reaches a preset target rotating speed, the engine is controlled to stop injecting fuel, and at the moment, the sound generated by the operation of the engine can be effectively reduced.

In this embodiment, the start control module 10 is further configured to control the torque of the engine through the compensation motor according to the working condition information of the vehicle, so as to control the engine to maintain a stable rotation speed;

in some embodiments of the present invention, the operating condition information of the vehicle is mainly operating condition parameters that dominate the power output of the vehicle, including but not limited to the engine water temperature of the vehicle, the battery pack power, and other parameter information.

When the working condition information of the automobile is good, the torque of the engine is controlled through a compensation motor in the hybrid power system, namely, a crankshaft and a piston of the engine are driven to move through the compensation motor, and the compensation motor controls the engine to keep a stable rotating speed.

A stop control module 20 for controlling the engine to be maintained at a target rotation speed by the compensation motor to enter a stop assist mode during a stop of the engine;

in this embodiment, the shutdown control module 30 is further configured to control the engine to stop when the engine does not receive a power request within a preset time after the target rotation speed is maintained for the preset time in the shutdown assistance mode.

In this embodiment, the start control module is specifically configured to:

acquiring an actual rotating speed in the starting process of an engine through a preset rotating speed sensor, and determining the rotating speed change rate of the engine according to the actual rotating speed of the engine;

calculating compensation torque required by the engine in a starting process according to the power parameter of the engine and the rotating speed change rate;

providing compensation torque for the engine through a preset compensation motor in a hybrid power system according to the calculated compensation torque required by the engine in the starting process;

the engine reaches a preset target rotating speed within a preset time by providing compensation torque to the engine, and the engine is controlled to stop supplying fuel into the cylinder after the engine reaches the target rotating speed.

In this embodiment, the shutdown control module is specifically configured to:

in the stopping process of the engine, recovering torque force generated in the running process of the engine through the compensating motor to keep the engine at a preset target rotating speed;

controlling the engine to enter a stop assist mode after the engine is maintained at the target speed.

Compared with the prior art, adopt the hybrid vehicle that shows among this embodiment to start and stop control system, beneficial effect lies in: during the starting process of the engine, a compensation motor provides compensation torque for the engine and controls the engine to keep a stable rotating speed; during the stopping process of the engine, the engine is controlled to be kept at a target rotating speed through the compensating motor so as to enter a stop auxiliary mode, and when the engine does not receive a power request within a preset time after the target rotating speed is kept for a preset time, the engine is controlled to stop working. The engine shutdown control method and the engine shutdown control device have the advantages that the NVH and the smoothness of the engine startup and shutdown are solved according to different vehicle speeds and working conditions, and meanwhile energy recovery is carried out in the shutdown process so as to achieve rapid shutdown of the engine.

Those of skill in the art will understand that the logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be viewed as implementing logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A start-stop control method for a hybrid electric vehicle is characterized by comprising the following steps:

in the starting process of the engine, calculating compensation torque required by the engine in the starting process according to the power parameter of the engine and the rotating speed change rate of the engine, providing the compensation torque to the engine through a compensation motor, and controlling the engine to stop supplying fuel after reaching a target rotating speed;

according to the working condition information of the automobile, the torque of the engine is controlled through the compensation motor, and the engine is controlled to keep a stable rotating speed;

controlling the engine to be kept at a target rotating speed through the compensating motor during the stopping process of the engine so as to enter a stopping auxiliary mode;

and under the stop auxiliary mode, when the engine maintains the target rotating speed for a preset time and does not receive a power request within the preset time, controlling the engine to stop working.

2. The method for controlling starting and stopping of a hybrid electric vehicle according to claim 1, wherein a compensation torque required by the engine during starting is calculated according to a preset torque compensation amplitude table and a rotation speed change rate of the engine, the compensation torque is provided to the engine through a compensation motor, and the step of controlling the engine to stop supplying fuel after reaching a target rotation speed specifically comprises:

acquiring an actual rotating speed in the starting process of an engine through a preset rotating speed sensor, and determining the rotating speed change rate of the engine according to the actual rotating speed of the engine;

calculating compensation torque required by the engine in a starting process according to the power parameter of the engine and the rotating speed change rate;

providing compensation torque for the engine through a preset compensation motor in a hybrid power system according to the calculated compensation torque required by the engine in the starting process;

the engine reaches a preset target rotating speed within a preset time by providing compensation torque to the engine, and the engine is controlled to stop supplying fuel into the cylinder after the engine reaches the target rotating speed.

3. The method for controlling starting and stopping of a hybrid electric vehicle according to claim 1, wherein the step of controlling the engine to maintain a stable rotation speed by controlling the torque of the engine through the compensation motor according to the working condition information of the vehicle specifically comprises:

acquiring working condition information of the automobile, wherein the working condition information at least comprises the current speed of the automobile, the water temperature of an engine and the electric quantity of a battery pack;

according to the working condition information, carrying out torque control on the engine through the compensation motor;

and when the compensation motor controls the torque of the engine, controlling the engine to keep a preset stable rotating speed.

4. The method for controlling starting and stopping of a hybrid electric vehicle according to claim 1, wherein the step of controlling the engine to maintain a target speed by the compensation motor to enter a stop assist mode specifically comprises:

in the stopping process of the engine, recovering the torque force generated in the running process of the engine through the compensating motor to keep the engine at a preset target rotating speed;

controlling the engine to enter a stop assist mode after the engine is maintained at the target speed.

5. The hybrid vehicle start-stop control method according to claim 1, further comprising:

in the stop assist mode, judging whether the engine receives a power request within a preset time when the target rotating speed is maintained;

and if not, controlling the engine to stop working.

6. The hybrid vehicle startup and shutdown control method according to any one of claims 1 to 5, characterized by further comprising:

and controlling the compensation motor to not provide compensation torque for the engine any more when the water temperature of the engine of the automobile exceeds a preset water temperature threshold value in the next starting process.

7. The hybrid vehicle startup and shutdown control method according to claim 6, characterized by further comprising:

and when the electric quantity of the battery pack is lower than a preset electric quantity threshold value, controlling the compensation motor to not provide compensation torque for the engine any more.

8. A hybrid vehicle start and stop control system, the system comprising:

the starting control module is used for calculating compensation torque required by the engine in the starting process according to a preset torque compensation amplitude table and the rotating speed change rate of the engine in the starting process of the engine, providing the compensation torque to the engine through a compensation motor, and controlling the engine to stop supplying fuel after reaching a target rotating speed;

the starting control module is also used for controlling the torque of the engine through the compensation motor according to the working condition information of the automobile and controlling the engine to keep a stable rotating speed;

the stopping control module is used for controlling the transmitter to be kept at a target rotating speed through the compensation motor so as to enter a stopping auxiliary mode during the stopping process of the engine;

the shutdown control module is further used for controlling the engine to stop working when the engine maintains the target rotating speed for a preset time and does not receive a power request within the preset time in the shutdown auxiliary mode.

9. The hybrid vehicle start and stop control system of claim 8, wherein the start control module is specifically configured to:

acquiring an actual rotating speed in the starting process of an engine through a preset rotating speed sensor, and determining the rotating speed change rate of the engine according to the actual rotating speed of the engine;

calculating compensation torque required by the engine in a starting process according to the power parameter of the engine and the rotating speed change rate;

providing compensation torque for the engine through a preset compensation motor in a hybrid power system according to the calculated compensation torque required by the engine in the starting process;

the engine reaches a preset target rotating speed within a preset time by providing compensation torque to the engine, and the engine is controlled to stop supplying fuel into the cylinder after the engine reaches the target rotating speed.

10. The hybrid vehicle start and stop control system according to claim 8, characterized in that: the shutdown control module is specifically configured to:

in the stopping process of the engine, recovering the torque force generated in the running process of the engine through the compensating motor to keep the engine at a preset target rotating speed;

controlling the engine to enter a stop assist mode after the engine is maintained at the target speed.

Images