CN116263132A

CN116263132A - Engine compression ratio control method, device and storage medium

Info

Publication number: CN116263132A
Application number: CN202111517790.7A
Authority: CN
Inventors: 罗海鹏; 占文锋; 吴广权; 江武
Original assignee: Guangzhou Automobile Group Co Ltd
Current assignee: Guangzhou Automobile Group Co Ltd
Priority date: 2021-12-13
Filing date: 2021-12-13
Publication date: 2023-06-16

Abstract

The invention discloses an engine compression ratio control method, a device and a storage medium, wherein the method comprises the following steps: determining a target compression ratio of an engine demand according to operation data of the vehicle, and determining whether compression ratio control of the engine is required according to the target compression ratio; if so, determining whether the compression ratio state of the engine is required to be switched according to the current working condition point and the target working condition point of the engine; if so, performing closed-loop control on the engine by taking the target compression ratio as a target, and controlling the engine according to pre-calibrated engine control parameter data in a transition region of compression ratio state switching; according to the invention, the compression ratio of the engine is controlled in a closed loop manner, and the transition region is controlled according to the calibrated engine control parameter data, so that the problem that the compression ratio is not smoothly switched can be effectively solved, the compression ratio between different working condition regions can be smoothly and stably switched, and the running stability of the engine is improved.

Description

Engine compression ratio control method, device and storage medium

Technical Field

The present invention relates to the field of engine control technologies, and in particular, to a method and apparatus for controlling an engine compression ratio, and a storage medium.

Background

The variable compression ratio technology of the engine is an engine revolutionary technology, the high compression ratio is adopted at low load of the engine, the thermal efficiency of the engine can be improved, the oil consumption is reduced, the low compression ratio is adopted at high load, the engine power and torque are improved, and the dynamic requirement is met.

The existing compression ratio control is based on a compression ratio mechanism and a compression ratio adjustable range, and is used for carrying out working condition partition control and generally comprises two types of components: one is a control strategy based on a two-stage compression ratio variable mechanism, which divides an engine operating condition into two specific regions, namely a high compression ratio region and a low compression ratio region, wherein the high compression ratio is adopted when the engine operating condition is in the high compression ratio region (running at low load), and the low compression ratio is adopted when the engine operating condition is in the low compression ratio region (running at high load); the second is a control strategy based on a continuously variable compression ratio mechanism that divides the engine operating conditions into three or more specific regions, and maintains the compression ratio at a certain value when the engine operating conditions are operating in the specific regions.

By adopting the two compression ratio control strategies to control the compression ratio of the engine, when the compression ratio state is switched between different working condition areas, the compression ratio is changed greatly, the problem that the compression ratio is not switched smoothly enough easily occurs, and the running stability and the high efficiency of the engine are affected.

Disclosure of Invention

The invention provides an engine compression ratio control method, an engine compression ratio control device and a storage medium, which are used for solving the problems that in the prior art, the engine compression ratio is not switched smoothly enough, and the running stability and the high efficiency of an engine are affected.

Provided is an engine compression ratio control method including:

determining a target compression ratio of an engine demand according to operation data of the vehicle, and determining whether compression ratio control of the engine is required according to the target compression ratio;

if the compression ratio of the engine is required to be controlled, determining whether the compression ratio state of the engine is required to be switched according to the current working condition point and the target working condition point of the engine;

and if the compression ratio state of the engine is required to be switched, performing closed-loop control on the engine by taking the target compression ratio as a target, and controlling the engine according to pre-calibrated engine control parameter data in a transition region of the compression ratio state switching.

Provided is an engine compression ratio control apparatus including:

the first determining module is used for determining a target compression ratio of the engine according to the running data of the vehicle and determining whether compression ratio control of the engine is required according to the target compression ratio;

The second determining module is used for determining whether the compression ratio state of the engine is required to be switched according to the current working condition point and the target working condition point of the engine if the compression ratio of the engine is required to be controlled;

and the control module is used for carrying out closed-loop control on the engine by taking the target compression ratio as a target if the compression ratio state of the engine is required to be switched, and controlling the engine according to the pre-calibrated engine control parameter data in a transition region of the compression ratio state switching.

There is provided an engine compression ratio control apparatus comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor executing the computer program to perform the steps of the engine compression ratio control method described above.

There is provided a readable storage medium storing a computer program which, when executed by a processor, implements the steps of the engine compression ratio control method described above.

In one scheme provided by the method, the device and the storage medium for controlling the engine compression ratio, the target compression ratio of the engine demand is determined according to the running data of the vehicle, and whether the engine needs to be controlled by the compression ratio is determined according to the target compression ratio; if the compression ratio of the engine is required to be controlled, determining whether the compression ratio state of the engine is required to be switched according to the current working condition point and the target working condition point of the engine; if the compression ratio state of the engine is required to be switched, performing closed-loop control on the engine by taking the target compression ratio as a target, and controlling the engine according to pre-calibrated engine control parameter data in a transition region of the compression ratio state switching; according to the invention, the compression ratio of the engine is controlled in a closed loop manner, and the engine is controlled in a transition region according to the pre-calibrated engine control parameter data, so that the accurate control of the compression ratio of the engine is realized, the problem that the compression ratio is not switched smoothly enough can be effectively solved, the compression ratio between different working condition regions can be switched smoothly and stably, and the running stability of the engine is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments of the present invention will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an engine compression ratio control system according to an embodiment of the present invention;

FIG. 2 is a flow chart of a method for controlling the compression ratio of an engine according to an embodiment of the invention;

FIG. 3 is a schematic representation of a zoning of engine operating regions in an embodiment of the present invention;

FIG. 4 is a schematic view showing a structure of an engine compression ratio control apparatus according to an embodiment of the present invention;

fig. 5 is another structural diagram of an engine compression ratio control apparatus in an embodiment of the invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The engine compression ratio control method provided by the embodiment of the invention can be applied to an engine compression ratio control system shown in fig. 1, wherein the engine control system comprises an engine and an engine compression ratio control device. Wherein the engine communicates with the engine compression ratio control device via a bus.

In the running process of the engine of the vehicle, the engine compression ratio control device needs to determine a target working condition point of the engine in advance according to running data (such as the requirement of accelerator opening and gear information) of the vehicle, further determines a target compression ratio of the engine according to the target working condition point, determines whether the engine needs to be subjected to compression ratio control according to the target compression ratio, and determines whether the engine needs to be subjected to compression ratio state switching when the engine needs to be subjected to compression ratio control; if the compression ratio state of the engine is required to be switched, performing closed-loop control on the engine by taking the target compression ratio as a target, and controlling the engine according to pre-calibrated engine control parameter data in a transition region of the compression ratio state switching; the compression ratio of the engine is controlled in a closed loop manner, and the engine is controlled according to the pre-calibrated engine control parameter data in a transition region where the compression ratio is switched, so that the accurate control of the compression ratio of the engine is realized, the problem that the compression ratio is not switched smoothly enough can be effectively solved, the compression ratio between different working condition regions can be switched smoothly and stably, and the running stability and the running efficiency of the engine are improved.

In this embodiment, the engine control system including the engine and the engine compression ratio control device is only exemplary, and in other embodiments, the engine control system further includes a compression ratio executing mechanism and various sensors, compression ratio sensors, etc., which are not described herein. The compression ratio actuator in this embodiment may be a motor or an electronic oil pump.

In one embodiment, as shown in fig. 2, there is provided an engine compression ratio control method, which is described by taking a server in fig. 1 as an example, including the steps of:

s10: a target compression ratio of the engine demand is determined, and it is determined whether compression ratio control of the engine is required.

In the engine running process of the vehicle, the engine compression ratio control device needs to acquire running data of the vehicle, wherein the running data of the vehicle comprise gear information and accelerator opening degree (or accelerator pedal position information, different accelerator pedal positions correspond to different accelerator opening degrees) of the vehicle, and the actual rotation speed, the actual load and the actual compression ratio of the engine. Wherein the actual compression ratio of the engine is detected by a compression ratio sensor.

After gear information and accelerator opening of the vehicle are obtained, the engine compression ratio control device determines a target working condition point which is required to be reached by the engine according to the gear information and the accelerator opening, determines a target rotating speed and a target load which correspond to the target working condition point, and further determines a target compression ratio which corresponds to the target working condition point, namely, a target compression ratio required by the engine according to the target rotating speed and the target load by determining and inquiring compression ratio data calibrated in advance.

The pre-calibrated compression ratio data are corresponding optimal compression ratios under different engine speeds and engine loads, and the optimal compression ratio data are determined by a whole vehicle test. In the pre-calibrated compression ratio data, dividing the engine speed and load into a plurality of working condition areas, wherein each working condition area corresponds to a target compression ratio, determining the area of a target working condition point according to the target speed and the target load after determining the target speed and the target load, and taking the target compression ratio of the area of the target working condition point as the target compression ratio of the engine requirement.

For example, engine speed and load are divided into two operating regions: the compression ratio control device comprises a first region and a second region, wherein the target compression ratio corresponding to the first region is a first target compression ratio, and the target compression ratio corresponding to the second region is a second target compression ratio; if the area where the target working point belongs is determined to be a first area according to the target rotating speed and the target load, the first target compression ratio is used as the target compression ratio of the engine requirement; and if the area where the target working point belongs is determined to be a second area according to the target rotating speed and the target load, taking the second target compression ratio as the target compression ratio of the engine requirement.

After the target compression ratio is determined, it is determined whether the compression ratio of the engine needs to be controlled based on the actual compression ratio and the target compression ratio of the engine. If the actual compression ratio is inconsistent with the target compression ratio, the compression ratio of the engine needs to be controlled; if the actual compression ratio matches the target compression ratio, the compression ratio of the engine does not need to be controlled.

S20: if compression ratio control of the engine is required, it is determined whether compression ratio state switching of the engine is required.

And determining whether compression ratio control is required for the engine according to the target compression ratio, and if the compression ratio control is required for the engine, determining whether compression ratio state switching is required for the engine by an engine compression ratio control device. The compression ratio state switching is to switch from one compression ratio state to another compression ratio state, such as from a high compression ratio state to a low compression ratio state, or from a low compression ratio state to a high compression ratio state.

The method comprises the steps of determining whether compression ratio state switching of an engine is needed or not, determining according to the compression ratio state of the current working condition point and the target working condition point of the engine, and if the compression ratio states of the current working condition point and the target working condition point are the same, namely, the current working condition point and the target working condition point are both in a high compression ratio state or a low compression ratio state, then the compression ratio state switching of the engine is not needed; if the compression ratio states of the two are different, the compression ratio state of the engine needs to be switched. And determining the compression ratio state according to the actual working condition of the engine so as to determine whether the compression ratio state is required to be switched or not, wherein the judgment result is more accurate.

In other embodiments, the difference between the actual compression ratio and the target compression ratio may be determined according to the difference between the actual compression ratio and the target compression ratio, and if the difference between the actual compression ratio and the target compression ratio is greater than a certain threshold, the compression ratio states of the actual compression ratio and the target compression ratio are different, the compression ratio needs to be switched; if the difference between the actual compression ratio and the target compression ratio is smaller than or equal to a certain threshold, the compression ratios of the actual compression ratio and the target compression ratio are identical, and the compression ratio does not need to be switched, and the engine is only required to be closed-loop controlled by taking the target compression ratio as a target. And whether the compression ratio state switching is needed or not is determined through difference judgment, so that the method is more direct and simple.

S20: and if the compression ratio state of the engine is required to be switched, performing closed-loop control on the engine by taking the target compression ratio as a target, and controlling the engine according to pre-calibrated engine control parameter data in a transition region of the compression ratio state switching.

If the compression ratio state switching of the engine is required, the compression ratio of the engine is closed-loop controlled by taking the target compression ratio as a target and adjusting the control parameters of the engine, and the engine is controlled according to the pre-calibrated engine control parameter data in the transition region of the compression ratio state switching. If the compression ratio state of the engine is required to be switched, which means that the region to which the target working point belongs is not the same region as the region to which the current working point belongs, in the process of performing closed-loop control on the compression ratio of the engine, the compression ratio of the engine is required to be switched from a high compression ratio state region to a low compression ratio state region or from the low compression ratio state region to the high compression ratio state region, so that in order to ensure smooth transition between the high compression ratio state and the low compression ratio state, in the transition region of the compression ratio state switching, the engine can be required to be controlled according to pre-calibrated engine control parameter data; and the first area (high compression ratio area) and the second area (low compression ratio area) at the two ends of the transition area can respectively control the compression ratio executing mechanism to be kept in a high compression ratio running state and a low compression ratio running state according to the traditional compression ratio control mode.

The engine control parameter data comprise relevant parameters such as fuel injection, ignition and the like of the engine. The pre-calibrated engine control parameter data includes first zone parameter data and second zone parameter data, and transition zone parameter data for controlling the engine in the transition zone. The control parameters of the engine in the transition zone are controlled through the pre-calibrated engine control parameters, so that the key transition zone between the high compression ratio zone and the low compression ratio zone can be accurately controlled, the engine can reasonably and smoothly transit to the high compression ratio zone or the low compression ratio zone, and the problem that the state switching of the compression ratio is not smooth enough can be effectively solved.

In this embodiment, the engine compression ratio control device determines a target compression ratio of an engine demand according to operation data of a vehicle, and determines whether compression ratio control of the engine is required according to the target compression ratio; if the compression ratio control is needed to be carried out on the engine, determining whether the compression ratio state switching is needed to be carried out on the engine or not; if the compression ratio state of the engine is required to be switched, performing closed-loop control on the engine by taking the target compression ratio as a target, and controlling the engine according to pre-calibrated engine control parameter data in a transition region of the compression ratio state switching; the compression ratio of the engine is controlled in a closed loop manner, and the engine is controlled according to the pre-calibrated engine control parameter data in a transition region of the state switching of the compression ratio, so that the problem that the state switching of the compression ratio is not smooth enough can be effectively solved, the compression ratio between different working condition regions can be smoothly and stably switched, and the running stability and the running efficiency of the engine are improved.

In one embodiment, in step S30, that is, in the transition region where the compression ratio state is switched, the engine is controlled according to the pre-calibrated engine control parameters, which specifically includes the following steps:

s31: determining the area of an initial working point of closed-loop control, wherein the area of the working point is determined according to the actual rotating speed and the actual load of the engine.

Before closed-loop control is performed on an engine, determining a region to which an initial operating point of the closed-loop control belongs, wherein the region to which the operating point of the engine belongs is determined according to the actual rotating speed and the actual load of the engine, and the region to which the operating point belongs comprises a first region and a second region. The method comprises the steps that before closed-loop control is carried out on an engine, the area where the current working condition point belongs is determined according to the actual rotating speed and the actual load of the engine, and the area where the current working condition point belongs is used as the initial working condition point of the closed-loop control.

As shown in fig. 3, to divide engine speed and loadThe first region (a region), the transition region (C region) and the second region (B region) are examples, wherein the transition region C is a working condition region between the first region a and the second region B. The horizontal axis of fig. 3 represents the rotation speed, the vertical axis represents the load, and the boundary rotation speed n between the first region a and the transition region C _h Boundary load b between first region a and transition region C _h The method comprises the steps of carrying out a first treatment on the surface of the Boundary load B between second region B and transition region C _l Boundary rotational speed n between second region B and transition region C _l The method comprises the steps of carrying out a first treatment on the surface of the Assuming that the actual rotation speed of the engine is n and the actual load of the engine is b, the area of the working point is determined by the following mode:

if n is not more than n _h And b is less than or equal to b _h The area of the current working point of the engine is a first area A;

if n _h ＜n＜n _l And b _h ＜b＜b _l The area of the current working point of the engine is a transition area C;

if n is greater than or equal to n _h And b is greater than or equal to b _h The region to which the current operating point of the engine belongs is a second region B.

S32: and if the area to which the initial working point belongs is the first area, controlling the engine according to the first area parameter data until the area to which the current working point belongs is determined to be the transition area.

In the embodiment, when the engine is subjected to closed-loop control, the engine is controlled in the whole process according to the pre-calibrated engine control parameters, so that the engine runs according to the calibration value, the accuracy and the high efficiency of the engine control are improved, and the smooth and stable switching of the high compression ratio state and the low compression ratio state of the engine is ensured. Wherein the pre-calibrated engine control parameters include first zone parameter data of the first zone (high compression ratio Map _A ) Second region parameter data of the second region (low compression ratio Map _B ) And transition zone parameter data of the transition zone, wherein the transition zone parameter data comprises first transition parameter data (Map of the transition zone calibrated at a high compression ratio _CH ) Second transition parameter data (Map with transition region calibrated at low compression ratio) _CL ) And third transition parameter data (Map _C )。

After determining the area of the starting operating point of the closed-loop control, if the area of the starting operating point is a first area A, which indicates that the engine is in a high compression ratio running state in the initial stage of the closed-loop control, and the rotation speed and load of the current operating point are smaller than those of the target operating point, the compression ratio executing mechanism is controlled to maintain the high compression ratio running state, and the compression ratio executing mechanism is controlled to maintain the high compression ratio running state according to the first area parameter data Map _A Controlling engines, i.e. engines according to Map _A The engine load is gradually increased and approaches to the target working point until the region of the current working point is determined to be a transition region C, namely the actual rotation speed of the engine exceeds the boundary rotation speed n _h The actual load of the engine crosses the boundary load b _h 。

S33: and controlling the engine in the transition region according to the pre-calibrated engine control parameter data until the region of the current working condition point is determined to be a second region.

When the engine enters the transition region, the compression ratio executing electric appliance is not in the original compression ratio state any more, but starts to perform compression ratio switching action, the engine is controlled according to the pre-calibrated engine control parameter data, the engine load is gradually increased until the actual rotation speed of the engine exceeds the boundary rotation speed n _l The actual load of the engine crosses the boundary load b _l And determining the area of the current working point as entering a second area so as to smoothly switch the high compression ratio state into the low compression ratio state.

S34: and in the second area, controlling the engine according to the second area parameter data until the actual compression ratio of the engine is the target compression ratio.

When entering the second area, the compression ratio actuating mechanism is controlled to keep a low compression ratio running state, and the engine Map is controlled according to the second area parameter data _B The engine is made to be Map _B And operating until the actual compression ratio of the engine is the target compression ratio, that is, until the actual compression ratio of the engine is the second target compression ratio of the second region.

In the embodiment, the area of the starting working point of closed-loop control is determined, and the area of the working point is determined according to the actual rotating speed and the actual load of the engine; if the area to which the initial working point belongs is a first area, controlling the engine according to the first area parameter data until the area to which the current working point belongs is determined to be a transition area, wherein the transition area is a working condition area between the first area and the second area; in the transition region, controlling the engine according to the pre-calibrated engine control parameter data until the region of the current working condition point is determined to enter a second region; in the second area, the engine is controlled according to the second area parameter data until the actual compression ratio of the engine is the target compression ratio, the specific step of performing closed-loop control on the engine by taking the target compression ratio as a target is clarified, and when the engine is switched from a high compression ratio state to a low compression ratio state, the engine is controlled according to the pre-calibrated engine control parameters in the whole process, so that the engine runs according to a calibration value, the accuracy and the high efficiency of engine control are improved, and the smooth and stable switching of the high compression ratio state and the low compression ratio state of the engine is ensured.

In one embodiment, in step S20, that is, in the transition region where the compression ratio state is switched, the engine is controlled according to the pre-calibrated engine control parameters, which specifically includes the following steps:

s35: and if the area to which the initial working point belongs is a second area, controlling the engine according to the second area parameter data until the area to which the current working point belongs is determined to be a transition area.

After determining the area of the starting operating point of the closed-loop control, if the area of the starting operating point is a second area B, indicating that the engine is in a low compression ratio running state in the initial stage of the closed-loop control, and at the moment, the rotating speed and the load of the current operating point are greater than those of the target operating point, controlling the compression ratio executing mechanism to keep the low compression ratio running state, and according to the second area parameter data Map _B Controlling engines, i.e. engines according to Map _B The engine load gradually drops and approaches to the target working point until the region of the current working point is determined to be a transition region C, namely the actual rotation speed of the engine exceeds the boundary rotation speed n _l The actual load of the engine crosses the boundary load b _l 。

S36: and in the transition region, controlling the engine according to the pre-calibrated engine control parameter data until the region where the current working condition point belongs is determined to be a first region.

When the engine enters the transition region, the compression ratio executing electric appliance is not in the original compression ratio state any more, but starts to perform compression ratio switching action, the engine is controlled according to the pre-calibrated engine control parameter data, the engine load is gradually reduced until the actual rotation speed of the engine exceeds the boundary rotation speed n _h The actual load of the engine crosses the boundary load b _h And determining the area of the current working point as entering the first area to smoothly switch the low compression ratio state into the high compression ratio state.

S37: and in the first area, controlling the engine according to the first area parameter data until the actual compression ratio of the engine is the target compression ratio.

When entering the first area, the compression ratio executing mechanism is controlled to maintain a high compression ratio running state, and the engine Map is controlled according to the first area parameter data _A The engine is made to be Map _A The operation is performed until the actual compression ratio of the engine is the target compression ratio, that is, until the actual compression ratio of the engine is the first target compression ratio of the first region.

In this embodiment, after determining the area to which the starting operating point of the closed-loop control belongs, if the area to which the starting operating point belongs is a second area, controlling the engine according to the second area parameter data until determining that the area to which the current operating point belongs is a transition area; in the transition region, controlling the engine according to pre-calibrated engine control parameter data until the region where the current working condition point belongs is determined to be a first region; in the first area, the engine is controlled according to the first area parameter data until the actual compression ratio of the engine is the target compression ratio, the specific step of performing closed-loop control on the engine by taking the target compression ratio as a target is clarified, and when the engine is switched from a low compression ratio state to a high compression ratio state, the engine is controlled according to the pre-calibrated engine control parameters in the whole process, so that the engine runs according to a calibration value, the accuracy and the high efficiency of the engine control are improved, and the smooth and stable switching of the high compression ratio state and the low compression ratio state of the engine is ensured.

In one embodiment, the pre-calibrated engine control parameters include first transition parameter data, second transition parameter data, and third transition parameter data. In step S20, that is, in the transition region where the compression ratio state is switched, the engine is controlled according to the pre-calibrated engine control parameters, specifically including the following steps:

s301: if the engine compression ratio control device has a preset function, interpolation processing is carried out on the control parameters of the engine in the transition region according to the first transition parameter data and the second transition parameter data.

If the engine compression ratio control device has a preset function, interpolation processing is carried out on the control parameters of the engine based on the actual working condition points of the engine in the transition region according to the first transition parameter data and the second transition parameter data.

In this embodiment, different transition zone control strategies are executed according to the functional state of the engine compression ratio control apparatus. When the engine compression ratio control device has a preset function, controlling the engine according to a first transition zone control strategy; and when the engine compression ratio control device does not have the preset function, controlling the engine according to the second transition zone control strategy. The preset function is a function capable of adding MAP or Bypass function, and if the engine compression ratio control device has Bypass function or MAP data can be added, the first transition region control strategy with higher precision can be executed, namely according to the first transition parameter data MAP _CH And second transition parameter data Map _CL Interpolation processing is carried out on the control parameters of the engine, so that the change of the control parameters of the engine is smoother, and the running stability of the engine is improved.

If the region to which the starting operating point of the closed-loop control belongs is the first region, when entering the transition region, the compression ratio executing electric appliance is not in the original compression ratio state any more, but starts to perform the compression ratio switching action, and then the electric appliance is controlled according to the first transition parameter data Map _CH And second transition parameter data Map _CL Interpolation processing is performed on the control parameters of the engine so that the engine load gradually increases until the actual rotation speed of the engine exceeds the boundary rotation speed n _l The actual load of the engine crosses the boundary load b _l Entering a second area; if the area to which the starting operating point belongs is the second area, when entering the transition area, the compression ratio executing electric appliance is not in the original compression ratio state any more, but starts to perform the compression ratio switching action, and then the electric appliance is switched according to the first transition parameter data Map _CH And second transition parameter data Map _CL Interpolation processing is carried out on the control parameters of the engine, the engine load gradually decreases until the actual rotation speed of the engine exceeds the boundary rotation speed n _h The actual load of the engine crosses the boundary load b _h Entering a first area.

In this embodiment, if the engine compression ratio control device has a preset function, the first transition parameter data and the second transition parameter data are obtained, and interpolation processing is performed on the control parameters based on the actual operating point of the engine according to the first transition parameter data and the second transition parameter data in the transition region where the compression ratio state is switched. In the transition region of the compression ratio state switching, namely, the first transition parameter data and the second transition parameter data are subjected to real-time interpolation processing, interpolation parameter data are generated, and the engine operates according to the interpolation parameter data, so that the control parameters are more accurate and smooth, the control precision of the engine is improved, and the operation condition change of the engine is more stable.

S302: and if the engine compression ratio control device does not have the preset function, controlling the control parameters of the engine according to the third transition parameter data in the transition region.

In this embodiment, if the engine compression ratio control device does not have the preset function, third transition preset parameter data is obtained, and in the transition region where the compression ratio state is switched, the control parameters of the engine are controlled according to the third transition parameter data. When the engine compression ratio control device does not have the Bypass function or MAP can not be newly increased, the engine is controlled to execute corresponding control parameters according to the third transition parameter data so as to smoothly transition to a target working condition point, and then the compression ratio of the engine is adjusted to be the target compression ratio.

If the region to which the starting operating point of the closed-loop control belongs is the first region, when entering the transition region, the compression ratio executing electric appliance is not in the original compression ratio state any more, but starts to perform the compression ratio switching action, and then the electric appliance is controlled according to the third transition parameter data Map _C The control parameters of the engine are controlled, the compression ratio executing mechanism acts according to the high compression ratio, the load of the engine is gradually increased until the actual rotation speed of the engine exceeds the boundary rotation speed n _h The actual load of the engine crosses the boundary load b _h Entering a second area; if the area to which the starting operating point belongs is the second area, when entering the transition area, the compression ratio executing electric appliance is not in the original compression ratio state any more, but starts to perform the compression ratio switching action, and then the electric appliance is switched according to the third transition parameter data Map _C Controlling the control parameters of the engine, the compression ratio executing mechanism acts according to the low compression ratio, the load of the engine gradually decreases until the actual rotation speed of the engine exceeds the boundary rotation speed n _l The actual load of the engine crosses the boundary load b _l Entering a first area.

In this embodiment, if the control device has a preset function, the engine compression ratio control device performs interpolation processing on the control parameters of the engine in the transition region according to the first transition parameter data and the second transition parameter data; if the engine compression ratio control device does not have the preset function, the engine compression ratio control device controls the control parameters of the engine in a transition area according to the third transition parameter data, a transition area switched in the compression ratio state is defined, specific steps for controlling the engine according to the pre-calibrated engine control parameters are carried out, different transition area control strategies are formulated for the engine compression ratio control device with different functions, the accuracy and the high efficiency of engine control are further improved, and therefore the stability of compression ratio transition is guaranteed.

In one embodiment, step S20, namely determining whether the engine needs to be switched between the compression ratio state and the state, specifically includes the following steps:

s21: and determining the area of the current working point according to the actual rotating speed and the actual load of the engine, and determining the area of the target working point according to the target compression ratio.

Determining an engine working condition area to which a current working condition point belongs according to the actual rotating speed and the actual load of the engine, namely determining the area to which the current working condition point belongs; and determining a target rotating speed and a target load according to the target compression ratio, so as to determine an engine working condition area to which the target working condition point belongs, namely determining an area to which the target working condition point belongs, according to the target rotating speed and the target load. The engine operating region includes a first region (high compression ratio region) and a second region; the compression ratio needs to be maintained in a high compression ratio state at the time of the first region, and thus the first region may be referred to as a high compression ratio region; the compression ratio needs to be maintained in a low compression ratio state at the time of the second region, and thus the second region may be referred to as a low compression ratio region.

S22: if the area to which the current working point belongs and the area to which the target working point belongs are not the same area, determining that the compression ratio state of the engine is required to be switched.

After the area of the current working point and the area of the target working point are determined, whether the area of the current working point and the area of the target working point are the same area or not is determined, if the area of the current working point and the area of the target working point are not the same area, the current compression ratio state and the target compression ratio state are different, and then the state switching of the compression ratio of the engine is determined.

S23: if the area to which the current working point belongs and the area to which the target working point belongs are the same area, it is determined that the compression ratio state of the engine is not required to be switched.

If the region to which the current working point belongs and the region to which the target working point belongs are the same region, which means that the current compression ratio state and the target compression ratio state are different and are both in a high compression ratio state or both in a low compression ratio state, it is determined that the compression ratio state of the engine is not required to be switched.

In the embodiment, determining a region where a current working point belongs according to the actual rotation speed and the actual load of the engine, and determining a region where a target working point belongs according to a target compression ratio; if the area to which the current working point belongs and the area to which the target working point belongs are not the same area, determining that the compression ratio state of the engine is required to be switched; if the area to which the current working point belongs and the area to which the target working point belongs are the same area, determining that the compression ratio state switching of the engine is not needed, determining whether the compression ratio state switching of the engine is needed or not by adopting the actual working point and the target working point, and determining whether the compression ratio state switching of the engine is needed or not is more accurate.

In one embodiment, after step S20, i.e. after determining whether a compression ratio state switching of the engine is required, the method specifically further comprises the steps of:

s50: if the compression ratio state of the engine is not required to be switched, performing closed-loop control on the engine according to the region to which the starting working point belongs and the target compression ratio:

after determining whether the compression ratio state of the engine is required to be switched, if the compression ratio state of the engine is not required to be switched, performing closed-loop control on the compression ratio of the engine by taking the target compression ratio as a target, and controlling the engine directly according to engine control parameters corresponding to the area to which the current working condition belongs as the compression ratio state switching between different working condition areas is not involved. Taking the example of dividing the working condition area of the engine into two areas, if the area of the current working condition is a first area (high compression ratio area), controlling the compression ratio executing mechanism to be kept in a high compression ratio running state, and controlling the engine to run according to the pre-calibrated first area parameter data; and if the area of the current working condition is a second area (low compression ratio area), controlling the compression ratio executing mechanism to be kept in a low compression ratio running state, and controlling the engine to run according to the pre-calibrated second area parameter data.

And (3) taking the target compression ratio as a target, performing closed-loop control on the engine according to the region to which the starting operating point belongs and according to pre-calibrated engine control parameter data, and specifically referring to step S51 or step S52.

S51: and if the area to which the starting working point belongs is a first area, taking the target compression ratio as a target, and performing closed-loop control on the compression ratio of the engine according to the first area parameter data.

After determining that the compression ratio state of the engine is not required to be switched, determining an engine working condition area to which a starting working condition of closed-loop control belongs, namely determining an area to which a starting working condition point belongs.

If the region to which the initial operating point belongs is a first region, which means that the target operating point corresponding to the target compression ratio is in the same region as the current operating point, the engine speed and load change need to be controlled, but the change region does not exceed the current first region, the target compression ratio is taken as a target, and Map is obtained according to the first region parameter data _A The compression ratio of the engine is closed-loop controlled, and the compression ratio executing mechanism is kept in a high compression ratio running state.

S52: and if the area to which the starting working point belongs is a second area, taking the target compression ratio as a target, and performing closed-loop control on the compression ratio of the engine according to the second area parameter data.

If the area to which the initial operating point belongs is a second area, which means that the target operating point corresponding to the target compression ratio and the current operating point are in the same area, the engine speed and load change need to be controlled, but the change area does not exceed the current second area, the target compression ratio is taken as the target, and the Map is obtained according to the second area parameter data _B The compression ratio of the engine is closed-loop controlled, and the compression ratio executing mechanism is kept in a low compression ratio running state.

In this embodiment, after determining whether the compression ratio state of the engine needs to be switched, if it is determined that the compression ratio state of the engine does not need to be switched, the engine is closed-loop controlled according to the region to which the starting operating point belongs and the target compression ratio: if the area of the starting working point is a first area, taking the target compression ratio as a target, and performing closed-loop control on the compression ratio of the engine according to the first area parameter data; if the area where the starting working condition point belongs is a second area, the target compression ratio is used as a target, the compression ratio of the engine is closed-loop controlled according to the second area parameter data, the specific process of performing closed-loop control on the engine is clarified when the state of the compression ratio of the engine is not required to be switched, and the accurate and efficient control on the compression ratio of the engine is realized by performing closed-loop control on the change of the actual compression ratio of the engine, so that the running stability of the engine is ensured.

In an embodiment, after step S30, i.e. after performing closed-loop control on the engine, the method specifically further comprises the following steps:

s61: in the closed-loop control process, the compression ratio change rate of the engine is monitored to determine whether the compression ratio change rate is within a preset rate range.

In the process of performing closed-loop control on the engine with the target compression ratio as a target, the engine compression ratio control device needs to monitor the compression ratio change rate of the engine to determine whether the compression ratio change rate is within a preset rate range. The preset speed range is determined according to the actual rotating speed and the actual load of the engine, and different engine rotating speeds and engine loads are calibrated in advance to form different preset speed ranges.

S62: and if the compression ratio change rate is not in the preset rate range, controlling the engine to alarm, and reducing the torque and the speed of the engine until the engine is stopped.

After determining whether the compression ratio change rate is within the preset rate range, if the compression ratio change rate is not within the preset rate range, the compression ratio change of the engine is too fast or too slow, so that the engine needs to be controlled to alarm and be reduced in torsion and speed until the engine is stopped, so that the safety of the engine is ensured.

In the present embodiment, the preset rate range at the actual rotation speed and the actual load of the engine includes a maximum rate of change value Δεr _max And a minimum rate of change value Δεr _min 。

For example, the engine compression ratio control device may be an Electronic Control Unit (ECU), and in the process of performing closed-loop control on the engine, the ECU monitors the compression ratio change rate of the engine in real time, and monitors the compression ratio change rate of the engine every one period t (t may be 1 engine cycle), where a calculation formula of the compression ratio change rate of the engine is:

Δεr _n+1 ＝εr _n+1 -εr _n ；

wherein, deltaεr _n+1 For the compression ratio change rate of the engine in the (n+1) th cycle (current cycle), εr _n+1 For the actual compression ratio of the engine in the current cycle εr _n Is the actual compression ratio of the nth cycle (last cycle) engine.

After determining whether the compression ratio change rate is within the preset rate range:

if delta epsilon r _min ≤Δεr _n+1 ≤Δεr _max Namely, the compression ratio change rate of the engine is larger than or equal to the minimum change rate allowed under the current rotating speed and the current load, and smaller than or equal to the maximum change rate allowed under the current rotating speed and the current load, which means that the compression ratio change rate of the engine is in a preset rate range, and the compression ratio change rate is in a safe range, and the engine is controlled to normally run;

If delta epsilon r _n+1 ＞Δεr _max The compression ratio change rate of the engine is larger than the maximum change rate allowed under the current rotating speed and the current load, which means that the compression ratio of the engine is too fast, and if the compression ratio change rate of the engine is determined not to be in the preset rate range, the engine needs to be controlled to alarm, and the engine is subjected to torque and speed reduction until the engine is stopped;

if delta epsilon r _n+1 ＜Δεr _min That is, the compression ratio change rate of the engine is smaller than the minimum change rate allowed under the current rotation speed and the current load, which means that the compression ratio change of the engine is too slow, and if the compression ratio change rate is not in the preset rate range, the engine needs to be controlled to alarm, and the engine is required to be reduced in torsion and speed until the engine is stopped.

In the embodiment, in the process of closed-loop control, the compression ratio change rate of the engine is monitored to determine whether the compression ratio change rate is in a preset rate range, and the preset rate range is determined according to the actual rotation speed and the actual load of the engine; and if the compression ratio change rate is not in the preset rate range, controlling the engine to alarm, and carrying out torque and speed reduction on the engine until stopping, so as to determine the safe operation of the engine.

s71: and monitoring the actual compression ratio of the engine in the closed-loop control process to determine whether the actual compression ratio meets the safety control requirement of the area where the current working point belongs.

In the process of performing closed-loop control on the engine by taking the target compression ratio as a target, the engine compression ratio control device needs to monitor the actual compression ratio of the engine so as to determine whether the actual compression ratio meets the safety control requirement of the area where the current working condition point belongs. The compression ratio of different engine working condition areas is different, so that different safety control requirements are set for the different engine working condition areas, and the operation safety of the engine is ensured on the basis of ensuring the accuracy of compression ratio regulation and control.

S72: and if the actual compression ratio does not meet the safety control requirement of the area where the current working point belongs, controlling the engine to alarm, and reducing the torque and the speed of the engine until the engine is stopped.

And if the actual compression ratio does not meet the safety control requirement of the area of the current working point, the condition that the fluctuation of the compression ratio of the engine is too large and potential safety hazards easily occur in the closed loop control process is indicated, the engine is controlled to alarm, and the engine is subjected to torque and speed reduction until the engine is stopped.

In the embodiment, the actual compression ratio of the engine is monitored in the closed-loop control process to determine whether the actual compression ratio meets the safety control requirement of the area where the current working point belongs; and if the actual compression ratio does not meet the safety control requirement of the area where the current working point belongs, controlling the engine to alarm, and performing torque and speed reduction on the engine until the engine is stopped, so that the operation safety of the engine is ensured on the basis of ensuring the accuracy of compression ratio regulation.

In one embodiment, in step S71, it is determined whether the actual compression ratio meets the safety control requirement of the area to which the current operating point belongs, and the method specifically includes the following steps:

s711: if the area to which the current working point belongs is the first area or the second area, determining a compression ratio difference value between the target compression ratio and the actual compression ratio, and determining whether the actual compression ratio meets the safety control requirement of the current compression ratio area according to the compression ratio difference value.

Monitoring the actual compression ratio of the engine in the process of closed loop control, determining the area of the current working point according to the actual rotation speed and the actual load of the engine, determining the compression ratio difference delta epsilon between the target compression ratio and the actual compression ratio if the area of the current working point is a first area or a second area, and determining the actual compression ratio epsilon according to the compression ratio difference delta epsilon _c Whether the safety control requirement of the current compression ratio region is satisfied. In the first region and the second region, the allowable compression ratio fluctuation value Δε and the compression ratio difference Δε may be used _limit Determining the actual compression ratio ε _c Whether the safety control requirement of the current compression ratio area is met; if the absolute value of the compression ratio difference delta epsilon is smaller than the compression ratio fluctuation delta epsilon _limit If the actual compression ratio fluctuation of the engine is not large, determining that the safety control requirement of the current compression ratio region is met; if the absolute value of the compression ratio difference delta epsilon is larger than or equal to the compression ratio fluctuation delta epsilon _limit And if the actual compression ratio fluctuation of the engine is too large, determining that the safety control requirement of the current compression ratio region is not met, controlling the engine to alarm, and reducing the speed and the torque until the engine is stopped so as to ensure the safety of the engine. In other embodiments, the safety control requirement of the current compression ratio region of the engine may be determined in other manners, which will not be described herein.

S712: if the area to which the current working point belongs is a transition area, determining a first target compression ratio of the first area and a second target compression ratio of the second area, and determining whether the actual compression ratio meets the safety control requirement of the current compression ratio area according to the first target compression ratio and the second target compression ratio.

If the area of the current working point is a transition area, determining a first target compression ratio epsilon of the first area _tA And a second target compression ratio epsilon of the second region _tB And according to a first target compression ratio epsilon _tA And a second target compression ratio epsilon _tB It is determined whether the actual compression ratio satisfies the safety control requirement of the current compression ratio region. Wherein the compression ratio is calculated based on the first target compression ratio, the second target compression ratio, and the compression ratio fluctuation value Deltaε _limit It is determined whether the actual compression ratio satisfies the safety control requirement of the current compression ratio region. If the actual compression ratio of the engine is greater than the first target compression ratio and the compression ratio fluctuation value delta epsilon _limit The sum of the compression ratio and the compression ratio fluctuation value delta epsilon is smaller than or equal to the second target compression ratio _limit The difference indicates that the actual compression ratio fluctuation of the engine is too large, and the safety control requirement of the current compression ratio area is determined not to be met; if the actual compression ratio of the engine is less than or equal to the first target compression ratio and the compression ratio fluctuation value delta epsilon _limit And is greater than or equal to the sum of the second target compression ratio and the compression ratio fluctuation value delta epsilon _limit And if the difference indicates that the actual compression ratio of the engine does not fluctuate greatly, determining that the safety control requirement of the current compression ratio region is met. In other embodiments, the determination may be performed by other parameters, which are not described herein.

In this embodiment, if the area to which the current operating point belongs is the first area or the second area, determining a compression ratio difference between the target compression ratio and the actual compression ratio, and determining whether the actual compression ratio meets the safety control requirement of the current compression ratio area according to the compression ratio difference, the compression ratio fluctuation lower limit threshold value and the compression ratio fluctuation upper limit threshold value; if the area to which the current working point belongs is a transition area, determining a first target compression ratio of the first area and a second target compression ratio of the second area, determining whether the actual compression ratio meets the safety control requirement of the current compression ratio area according to the first target compression ratio, the second target compression ratio, a compression ratio fluctuation lower limit threshold value and a compression ratio fluctuation upper limit threshold value, determining whether the actual compression ratio meets the safety control requirement of the area to which the current working point belongs, determining the specific step of determining whether the actual compression ratio meets the safety control requirement of the area to which the current working point belongs, and directly evaluating the compression ratio fluctuation condition according to the compression ratio difference value between the target compression ratio and the actual compression ratio as an evaluation parameter in the first area and the second area with the compression ratio control targets; in a transition region where no compression ratio control target exists, the compression ratio fluctuation condition of the transition region is evaluated based on the compression ratio control targets of the first region and the second region as references, and it is ensured that the compression ratio change can be smoothly switched.

In an embodiment, in step S711, that is, according to the compression ratio difference, it is determined whether the actual compression ratio meets the safety control requirement of the current compression ratio region, which specifically includes the following steps:

s7111: when the compression ratio difference is a positive value, it is determined whether the compression ratio difference is smaller than a compression ratio fluctuation lower limit threshold.

In this embodiment, different compression ratio fluctuation thresholds are set according to different compression ratio switching conditions, including a compression ratio fluctuation lower limit threshold Δε _llimit And a compression ratio fluctuation upper limit threshold value delta epsilon _ulimit 。

When Deltaε > 0, i.e. the difference between the target compression ratio and the actual compression ratio is positive, it indicates that the actual compression is smaller than the target compression ratio, the compression ratio control system determines whether or not it is smaller than the compression ratio fluctuation lower limit threshold Deltaε _llimit . If Deltaepsilon < Deltaepsilon _llimit I.e. the compression ratio difference is less than the compression ratio fluctuation lower threshold delta epsilon _llimit Then consider the current compression ratio epsilon _c And within the allowable deviation, determining that the actual compression ratio meets the safety control requirement of the current compression ratio region, and controlling the engine to work normally.

S7112: and if the compression ratio difference is greater than or equal to the compression ratio fluctuation lower limit threshold, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region.

Determining whether a compression ratio difference between a target compression ratio and an actual compression ratio of an engine is less than a compression ratio fluctuation lower limit threshold value delta epsilon _llimit After that, if Deltaepsilon is larger than or equal to Deltaepsilon _llimit I.e. the compression ratio difference is greater than or equal to the compression ratio fluctuation lower threshold Δε _llimit Then consider to be currentCompression ratio epsilon _c And deviating from the target, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region, controlling the engine to alarm at the moment, limiting the speed and the torque, and finally stopping the engine.

S7113: when the compression ratio difference is a negative value, it is determined whether the absolute value of the compression ratio difference is less than the compression ratio fluctuation upper limit threshold.

When Δε < 0, that is, when the compression ratio difference between the target compression ratio and the actual compression ratio is a negative value, indicating that the actual compression is larger than the target compression ratio, the compression ratio control system determines whether the absolute value of the compression ratio difference is smaller than the compression ratio fluctuation upper limit threshold Δε _ulimit . If |Deltaε| < Deltaε _ulimit I.e. the absolute value of the compression ratio difference is less than the upper compression ratio fluctuation threshold delta epsilon _ulimit Then consider the current compression ratio epsilon _c And within the allowable deviation, determining that the actual compression ratio meets the safety control requirement of the current compression ratio region, and controlling the engine to work normally.

S7114: and if the absolute value of the compression ratio difference value is larger than or equal to the compression ratio fluctuation upper limit threshold value, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region.

In determining whether the absolute value of the compression ratio difference is greater than the compression ratio fluctuation upper limit threshold value delta epsilon _ulimit Thereafter, if |Δε| > Δε _ulimit I.e. the absolute value of the compression ratio difference is greater than the upper compression ratio fluctuation threshold Δε _ulimit Then consider the current compression ratio epsilon _c And if the actual compression ratio deviates from the target, determining that the actual compression ratio meets the safety control requirement of the current compression ratio region, controlling the engine to alarm at the moment, limiting the speed and the torque, and finally stopping the engine.

In this embodiment, when the compression ratio difference is a positive value, it is determined whether the compression ratio difference is smaller than a compression ratio fluctuation lower limit threshold, and if the compression ratio difference is greater than or equal to the compression ratio fluctuation lower limit threshold, it is determined that the actual compression ratio does not meet the safety control requirement of the current compression ratio region; when the compression ratio difference is a negative value, determining whether the absolute value of the compression ratio difference is smaller than the compression ratio fluctuation upper limit threshold, if the absolute value of the compression ratio difference is larger than or equal to the compression ratio fluctuation upper limit threshold, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region, determining whether the actual compression ratio meets the safety control requirement of the current compression ratio region according to the compression ratio difference, evaluating different compression ratio conditions by adopting different compression ratio fluctuation upper limit thresholds, and further ensuring the compression ratio safety in different switching processes, thereby ensuring the safe operation of an engine.

In an embodiment, in step S712, that is, according to the first target compression ratio and the second target compression ratio, it is determined whether the actual compression ratio meets the safety control requirement of the current compression ratio region, which specifically includes the following steps:

s7121: and taking the difference between the second target compression ratio and the compression ratio fluctuation lower limit threshold value as the minimum compression ratio.

S7122: and taking the sum of the first target compression ratio and the compression ratio fluctuation upper limit threshold as the maximum compression ratio.

S7123: it is determined whether the actual compression ratio is smaller than the minimum compression ratio, and it is determined whether the actual compression ratio is larger than the maximum compression ratio.

S7124: if the actual compression ratio is smaller than the minimum compression ratio or the actual compression ratio is larger than the maximum compression ratio, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region.

Then, the second target compression ratio ε _tB And a compression ratio fluctuation lower limit threshold delta epsilon _llimit As a minimum compression ratio, and a first target compression ratio epsilon _tA And the compression ratio fluctuation upper limit threshold delta epsilon _ulimit As the maximum compression ratio, it is then determined whether the actual compression ratio is smaller than the minimum compression ratio, and it is determined whether the actual compression ratio is larger than the maximum compression ratio. If epsilon _c ＜ε _tB -Δε _llimit Or epsilon _c ＜ε _tA +Δε _ulimit I.e. actual pressureScaling epsilon _c Is smaller than the minimum compression ratio, or the actual compression ratio epsilon c is larger than the maximum compression ratio, the current compression ratio epsilon is considered _c If the actual compression ratio deviates from the target range, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region; if epsilon _tB -Δε _llimit ≤ε _c ≤ε _tA +Δε _ulimit I.e. the actual compression ratio is greater than or equal to the minimum compression ratio and the actual compression ratio is less than or equal to the maximum compression ratio, the current compression ratio epsilon of the task _c And if the actual compression ratio meets the safety control requirement of the current compression ratio region, controlling the engine to normally run.

In this embodiment, the difference between the second target compression ratio and the lower limit threshold of the compression ratio fluctuation is used as the minimum compression ratio, the sum of the first target compression ratio and the upper limit threshold of the compression ratio fluctuation is used as the maximum compression ratio, then it is determined whether the actual compression ratio is smaller than the minimum compression ratio and whether the actual compression ratio is larger than the maximum compression ratio, if the actual compression ratio is smaller than the minimum compression ratio or the actual compression ratio is larger than the maximum compression ratio, it is determined that the actual compression ratio does not meet the safety control requirement of the current compression ratio region, the specific steps of determining whether the actual compression ratio meets the safety control requirement of the current compression ratio region according to the first target compression ratio and the second target compression ratio are defined, different compression ratio fluctuation upper limit thresholds are adopted, and the compression ratio change of the transition region is controlled by combining with the compression ratio targets of other regions, so that the safety of the compression ratios in different switching processes is further ensured, and the safe operation of the engine is ensured.

In an embodiment, before step S10, i.e. before determining the target compression ratio of the engine demand according to the vehicle operation data, the method specifically further comprises the steps of:

s01: after the engine is powered up, it is determined whether the compression ratio sensor and the compression ratio actuator are malfunctioning.

After the engine is powered on, controlling and checking whether the compression ratio sensor fails; and after the engine ECU is electrified each time, the compression ratio executing mechanism (a motor or an electronic oil pump) is controlled to carry out self-checking so as to determine whether the compression ratio executing mechanism has any fault conditions such as hardware damage, incapacity of being electrified, unreasonable signals and the like. If the compression ratio sensor is normal and has no fault, and the compression ratio executing mechanism is normal and has no fault, entering a normal mode, and determining a target compression ratio of the engine demand according to the running data of the vehicle so as to carry out closed-loop control on the engine according to the target compression ratio.

S02: and if the compression ratio sensor fails and the compression ratio executing mechanism does not fail, alarming, and controlling the engine according to the failure parameter data.

After determining whether the compression ratio sensor and the compression ratio executing mechanism are faulty, if the compression ratio sensor is faulty, but the compression ratio executing mechanism is not faulty, and the actual compression ratio cannot be obtained in time, accurate closed-loop control on the compression ratio of the engine cannot be performed, but the compression ratio executing mechanism can still operate, the compression ratio executing mechanism is controlled to operate according to the high compression ratio state, and the engine is controlled according to fault parameter data (pre-calibrated engine control parameter data when the sensor is faulty), so that the engine operates in a Map area with the high compression ratio, and an alarm is given at the same time to prompt a user that the compression ratio sensor is faulty.

S03: and if the compression ratio sensor fails and the compression ratio executing mechanism fails, controlling the engine to alarm, and limiting the speed and the torque of the engine until the engine is stopped.

If the compression ratio sensor fails and the compression ratio executing mechanism fails, the actual compression ratio cannot be obtained in time, and the compression ratio executing mechanism cannot operate, namely the compression ratio executing mechanism cannot accept an execution command fed back by the ECU to perform compression ratio maintaining and switching actions, namely the compression ratio is out of control, the engine is controlled to alarm, the engine is limited in speed and torque until the engine is stopped, and the compression ratio system is controlled to enter a fault mode.

In this embodiment, through carrying out fault detection to compression ratio sensor and compression ratio actuating mechanism, break down at compression ratio sensor, and compression ratio actuating mechanism breaks down, then control the engine and report to the police to limit the speed limit to turn round to shut down to the engine, can avoid engine part further damage, can reduce whole car and personnel's incident to a certain extent.

It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic, and should not limit the implementation process of the embodiment of the present invention.

In one embodiment, an engine compression ratio control apparatus is provided that corresponds one-to-one to the engine compression ratio control method in the above embodiment. As shown in fig. 4, the engine compression ratio control apparatus includes a first determination module 401, a second determination module 402, and a control module 403. The functional modules are described in detail as follows:

a first determining module 401 for determining a target compression ratio of the engine demand according to the operation data of the vehicle, and determining whether compression ratio control of the engine is required according to the target compression ratio;

a second determining module 402, configured to determine whether the compression ratio state of the engine needs to be switched if the compression ratio of the engine needs to be controlled;

and the control module 403 is configured to perform closed-loop control on the engine with the target compression ratio as the target if the compression ratio state of the engine needs to be switched, and control the engine according to the pre-calibrated engine control parameter data in the transition region of the compression ratio state switching.

Further, the pre-calibrated engine control parameters include first transition parameter data, second transition parameter data, and third transition parameter data, and the control module 403 is specifically configured to:

If the control device has a preset function, performing interpolation processing on control parameters of the engine in a transition region according to the first transition parameter data and the second transition parameter data;

and if the engine compression ratio control device does not have the preset function, controlling the control parameters of the engine according to the third transition parameter data in the compression ratio transition region.

Further, the control module 403 is specifically further configured to:

determining a region of an initial working point of closed-loop control, wherein the region of the working point is determined according to the actual rotating speed and the actual load of the engine;

if the area to which the initial working point belongs is a first area, controlling the engine according to the first area parameter data until the area to which the current working point belongs is determined to be a transition area, wherein the transition area is a working condition area between the first area and the second area;

in the transition region, controlling the engine according to the pre-calibrated engine control parameter data until the region of the current working condition point is determined to enter a second region;

and in the second area, controlling the engine according to the second area parameter data until the actual compression ratio of the engine is the target compression ratio, wherein the first area parameter data and the second area parameter data are both pre-calibrated engine control parameter data.

Further, after determining the region to which the starting operating point of the closed-loop control belongs, the control module 403 is specifically further configured to:

if the area of the initial working point is the second area, controlling the engine according to the second area parameter data until the area of the current working point is determined to be a transition area;

in the transition region, controlling the engine according to pre-calibrated engine control parameter data until the region where the current working condition point belongs is determined to be a first region;

and in the first area, controlling the engine according to the first area parameter data until the actual compression ratio of the engine is the target compression ratio.

Further, the control module 403 is specifically further configured to:

determining the area of the current working point according to the actual rotating speed and the actual load of the engine, and determining the area of the target working point according to the target compression ratio;

if the area to which the current working point belongs and the area to which the target working point belongs are not the same area, determining that the compression ratio state of the engine is required to be switched;

if the area to which the current working point belongs and the area to which the target working point belongs are the same area, it is determined that the compression ratio state of the engine is not required to be switched.

Further, after determining whether the engine needs to be switched to the compression ratio state, the control module 403 is specifically further configured to:

If the compression ratio state of the engine is not required to be switched, performing closed-loop control on the engine according to the region to which the starting working point belongs and the target compression ratio:

if the area of the starting working point is a first area, taking the target compression ratio as a target, and performing closed-loop control on the compression ratio of the engine according to the first area parameter data;

and if the area to which the starting working point belongs is a second area, taking the target compression ratio as a target, and performing closed-loop control on the compression ratio of the engine according to the second area parameter data.

Further, the engine compression ratio control apparatus further includes a monitoring module 404, where after performing closed-loop control on the engine, the monitoring module 404 is specifically configured to:

in the closed-loop control process, monitoring the compression ratio change rate of the engine to determine whether the compression ratio change rate is in a preset rate range, wherein the preset rate range is determined according to the actual rotating speed and the actual load of the engine;

and if the compression ratio change rate is not in the preset rate range, controlling the engine to alarm, and reducing the torque and the speed of the engine until the engine is stopped.

Further, after performing closed-loop control on the engine, the monitoring module 404 is specifically further configured to:

Monitoring the actual compression ratio of the engine in the closed-loop control process to determine whether the actual compression ratio meets the safety control requirement of the area where the current working point belongs;

and if the actual compression ratio does not meet the safety control requirement of the area where the current working point belongs, controlling the engine to alarm, and reducing the torque and the speed of the engine until the engine is stopped.

Further, the monitoring module 404 is specifically further configured to:

if the area to which the current working point belongs is a first area or a second area, determining a compression ratio difference value between the target compression ratio and the actual compression ratio, and determining whether the actual compression ratio meets the safety control requirement of the current compression ratio area according to the compression ratio difference value;

if the area to which the current working point belongs is a transition area, determining a first target compression ratio of the first area and a second target compression ratio of the second area, and determining whether the actual compression ratio meets the safety control requirement of the current compression ratio area according to the first target compression ratio and the second target compression ratio.

Further, the monitoring module 404 is specifically further configured to:

when the compression ratio difference is a positive value, determining whether the compression ratio difference is smaller than a compression ratio fluctuation lower limit threshold;

If the compression ratio difference is larger than or equal to the compression ratio fluctuation lower limit threshold, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region;

when the compression ratio difference is a negative value, determining whether the absolute value of the compression ratio difference is smaller than an upper limit threshold of compression ratio fluctuation;

and if the absolute value of the compression ratio difference value is larger than or equal to the compression ratio fluctuation upper limit threshold value, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region.

Further, the monitoring module 404 is specifically further configured to:

taking the difference between the second target compression ratio and the compression ratio fluctuation lower limit threshold value as the minimum compression ratio;

taking the sum of the first target compression ratio and the compression ratio fluctuation upper limit threshold as the maximum compression ratio;

determining whether the actual compression ratio is smaller than the minimum compression ratio, and determining whether the actual compression ratio is larger than the maximum compression ratio;

if the actual compression ratio is smaller than the minimum compression ratio or the actual compression ratio is larger than the maximum compression ratio, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region.

The specific limitation of the engine compression ratio control apparatus may be referred to as limitation of the engine compression ratio control method hereinabove, and will not be described in detail herein. The respective modules in the above-described engine compression ratio control apparatus may be implemented in whole or in part by software, hardware, or a combination thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.

In one embodiment, an engine compression ratio control apparatus is provided, which may be an engine ECU. The engine compression ratio control device comprises a processor and a memory which are connected through a system bus. Wherein the processor of the engine compression ratio control apparatus is configured to provide computing and control capabilities. The memory of the engine compression ratio control device comprises a storage medium and an internal memory. The storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer programs in the storage media. The computer program is executed by a processor to implement a method of controlling an engine compression ratio.

In one embodiment, as shown in fig. 5, there is provided an engine compression ratio control apparatus including a memory, a processor, and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the engine compression ratio control method described above when executing the computer program.

In one embodiment, a computer readable storage medium is provided having a computer program stored thereon, which when executed by a processor, implements the steps of the engine compression ratio control method described above.

Those skilled in the art will appreciate that implementing all or part of the above-described methods may be accomplished by way of a computer program stored on a computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the various embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions.

The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and are intended to be included in the scope of the present invention.

Claims

1. An engine compression ratio control method, characterized by comprising:

determining a target compression ratio of an engine demand according to operation data of a vehicle, and determining whether compression ratio control of the engine is required according to the target compression ratio;

If the compression ratio control is needed to be carried out on the engine, determining whether the compression ratio state switching is needed to be carried out on the engine or not;

2. The engine compression ratio control method according to claim 1, wherein the pre-calibrated engine control parameters include first transition parameter data, second transition parameter data, and third transition parameter data, the engine being controlled in the transition region where the compression ratio state is switched according to the pre-calibrated engine control parameters, comprising:

if the control device has a preset function, performing interpolation processing on the control parameters of the engine in the transition region according to the first transition parameter data and the second transition parameter data;

3. The engine compression ratio control method according to claim 1, characterized in that the closed-loop control of the engine targeting the target compression ratio includes:

determining a region of an initial working point of the closed-loop control, wherein the region of the working point is determined according to the actual rotating speed and the actual load of the engine;

if the area to which the starting working point belongs is a first area, controlling the engine according to the first area parameter data until the area to which the current working point belongs is determined to be the transition area, wherein the transition area is a working area between the first area and the second area;

in the transition region, controlling the engine according to the pre-calibrated engine control parameter data until the region of the current working point is determined to enter the second region;

and in the second area, controlling the engine according to second area parameter data until the actual compression ratio of the engine is the target compression ratio, wherein the first area parameter data and the second area parameter data are both pre-calibrated engine control parameter data.

4. The engine compression ratio control method according to claim 3, characterized in that after the determination of the region to which the start operating point of the closed-loop control belongs, the method further comprises:

If the area to which the starting working point belongs is the second area, controlling the engine according to the second area parameter data until the area to which the current working point belongs is determined to be the transition area;

in the transition region, controlling the engine according to the pre-calibrated engine control parameter data until the region to which the current working point belongs is determined to be the first region;

5. The engine compression ratio control method according to claim 1, characterized in that the determining whether the engine needs to be subjected to compression ratio state switching includes:

if the area of the current working point is not the same area as the area of the target working point, determining that the compression ratio state of the engine is required to be switched;

and if the area to which the current working point belongs and the area to which the target working point belongs are the same area, determining that the compression ratio state of the engine is not required to be switched.

6. The engine compression ratio control method according to claim 1, characterized in that after the determination of whether the engine needs to be subjected to a compression ratio state switching, the method further comprises:

if the area to which the starting working point belongs is a first area, taking the target compression ratio as a target, and performing closed-loop control on the compression ratio of the engine according to first area parameter data;

and if the area to which the starting working point belongs is a second area, taking the target compression ratio as a target, and performing closed-loop control on the compression ratio of the engine according to second area parameter data.

7. The engine compression ratio control method according to any one of claims 1 to 6, characterized in that after the engine is closed-loop controlled, the method further comprises:

monitoring the compression ratio change rate of the engine in the closed-loop control process to determine whether the compression ratio change rate is in a preset rate range, wherein the preset rate range is determined according to the actual rotating speed and the actual load of the engine;

8. The engine compression ratio control method according to any one of claims 1 to 6, characterized in that after the engine is closed-loop controlled, the method further comprises:

9. The engine compression ratio control method according to claim 8, wherein the determining whether the actual compression ratio satisfies a safety control requirement of an area to which a current operating point belongs includes:

If the area to which the current working point belongs is the transition area, determining a first target compression ratio of the first area and a second target compression ratio of the second area, and determining whether the actual compression ratio meets the safety control requirement of the current compression ratio area according to the first target compression ratio and the second target compression ratio.

10. The engine compression ratio control method according to claim 9, wherein the determining whether the actual compression ratio satisfies a safety control requirement of a current compression ratio region based on the compression ratio difference value includes:

if the compression ratio difference value is larger than or equal to the compression ratio fluctuation lower limit threshold value, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region;

when the compression ratio difference is a negative value, determining whether the absolute value of the compression ratio difference is smaller than a compression ratio fluctuation upper limit threshold;

11. The engine compression ratio control method according to claim 9, characterized in that the determining whether the actual compression ratio satisfies a safety control requirement of a current compression ratio region according to the first target compression ratio and the second target compression ratio includes:

taking the difference between the second target compression ratio and the compression ratio fluctuation lower limit threshold value as a minimum compression ratio;

taking the sum of the first target compression ratio and the compression ratio fluctuation upper limit threshold as a maximum compression ratio;

determining whether the actual compression ratio is less than the minimum compression ratio, and determining whether the actual compression ratio is greater than the maximum compression ratio;

and if the actual compression ratio is smaller than the minimum compression ratio or the actual compression ratio is larger than the maximum compression ratio, determining that the actual compression ratio does not meet the safety control requirement of the current compression ratio region.

12. An engine compression ratio control apparatus, characterized by comprising:

the first determining module is used for determining a target compression ratio of an engine according to running data of the vehicle and determining whether compression ratio control of the engine is needed according to the target compression ratio;

the second determining module is used for determining whether the compression ratio state of the engine is required to be switched if the compression ratio of the engine is required to be controlled;

13. An engine compression ratio control apparatus comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the engine compression ratio control method according to any one of claims 1 to 11 when executing the computer program.

14. A readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the engine compression ratio control method according to any one of claims 1 to 11.