CN113700565A - Control method and device of variable compression ratio engine and engine control system - Google Patents
Control method and device of variable compression ratio engine and engine control system Download PDFInfo
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Abstract
The invention discloses a control method and a control device of a variable compression ratio engine and an engine control system, wherein the method comprises the following steps: determining an opening duration basic value and an opening time basic value of a control valve based on actual operation condition data of an engine; correcting the basic value of the opening duration based on a compression ratio deviation correction coefficient and a water temperature correction coefficient, wherein the compression ratio deviation correction coefficient is determined based on the deviation of a set compression ratio and a detected actual compression ratio, and the water temperature correction coefficient is determined based on the water temperature of the engine; and taking the minimum value of the corrected basic value of the opening duration and the preset maximum opening duration as a target opening duration, and if the target opening duration is greater than the preset minimum opening duration, controlling the opening of the control valve based on the basic value of the opening time of the control valve and the target opening duration so as to adjust the compression ratio of the engine. The control method can accurately realize the control of the engine compression ratio.
Description
Technical Field
The invention relates to the technical field of engines, in particular to a control method and device of a variable compression ratio engine and an engine control system.
Background
At present, the gasoline engine is subject to the pressure of oil consumption regulations, a variable compression ratio technology is adopted to improve the heat efficiency of the engine, the driving force for changing the compression ratio mainly comes from a hydraulic mechanism driving system and a motor driving system at present, wherein the hydraulic driving system is adopted to adjust the oil amount in different cavities through a hydraulic valve, so that a gear connecting rod mechanism for adjusting the compression ratio moves to change the position of the top dead center of a piston, and the variable compression ratio is realized, wherein the control precision of the hydraulic system to control the valve is difficult.
In actual use, the problem of poor control of the actual compression ratio exists in the variable compression ratio gasoline engine driven by the hydraulic mechanism, and the specific expression is as follows: the accuracy of the control of the compression ratio is poor, i.e. the difference between the actual value of the compression ratio and the desired value of the compression ratio exceeds the required range, followed by a runaway compression ratio, i.e. the actual value of the compression ratio does not run against the desired value of the compression ratio. The problem of poor control precision of the compression ratio causes the knocking tendency of an engine and the whole vehicle to be serious, and the emission and the oil consumption to be deteriorated, so that the driving experience of a client is poor. And the problem of the compression ratio out of control has the risk of damaging a compression ratio control mechanism, so that the engine is irreversibly damaged.
Disclosure of Invention
The embodiment of the application provides a control method and a control device of a variable compression ratio engine and an engine control system, and the method can accurately realize the control of the compression ratio of the engine, so that the engine can safely and stably run in different working condition areas.
In a first aspect, the present invention provides the following technical solutions through an embodiment of the present invention:
a control method of a variable compression ratio engine, applied in an engine control system including a hydraulic mechanism in which a hydraulic flow control valve is used to control a compression ratio of the engine, the method comprising: determining an opening duration basic value and an opening time basic value of the control valve based on actual operation condition data of the engine; correcting the opening duration basic value based on a compression ratio deviation correction coefficient and a water temperature correction coefficient, wherein the compression ratio deviation correction coefficient is determined based on the deviation of a set compression ratio and a detected actual compression ratio, and the water temperature correction coefficient is determined based on the engine water temperature; and taking the minimum value of the corrected basic value of the opening duration and the preset maximum opening duration as a target opening duration, and if the target opening duration is greater than the preset minimum opening duration, controlling the opening of the control valve based on the basic value of the opening time of the control valve and the target opening duration so as to adjust the compression ratio of the engine.
Preferably, the controlling the control valve to be opened based on the opening timing base value of the control valve and the target opening duration includes: determining a starting time correction value based on the opening duration of the control valve, and correcting the opening time basic value of the control valve based on the starting time correction value to obtain a corrected opening time basic value; obtaining the opening time of the control valve based on the corrected opening time basic value and the control valve opening delay time, wherein the control valve opening delay time is obtained based on the rotating speed of the engine; taking the maximum value from the obtained opening time and the preset minimum opening time of the control valve as the target opening time of the control valve; and controlling the opening of the control valve based on the target opening time and the target opening duration.
Preferably, the actual operating condition data includes: the engine comprises an operating mode of the engine, a rotating speed of the engine and an air intake quantity, wherein the operating mode comprises a combustion mode and a dragging mode.
Preferably, after the modifying the opening duration basic value based on the compression ratio deviation modification coefficient and the water temperature modification coefficient, the method further includes: and correcting the corrected opening duration basic value based on a preset opening delay time and a preset closing delay time, wherein the opening delay time and the closing delay time are respectively determined based on the rotating speed of the engine and the air inflow.
Preferably, the modifying the modified basic value of the opening duration based on the preset opening delay time and the preset closing delay time specifically includes: increasing the opening delay time over an opening time of the control valve and decreasing the closing delay time over a closing time of the control valve.
Preferably, before determining the basic value of the opening duration of the control valve based on the actual operating condition data of the engine, the method further comprises: when the detected resultant force direction required by the target compression ratio adjustment amount is the same as the actual resultant force direction of the current control window of the engine, sending an opening time and an opening duration command of the control valve, wherein the resultant force is the resultant force of combustion pressure, inertia force and pressure difference between an upper oil chamber and a lower oil chamber in the engine control system; and responding to the opening time and the opening duration command, and executing the step of determining the opening duration basic value of the control valve based on the actual operation condition data of the engine.
Preferably, the maximum opening period and the minimum opening period are determined based on actual operating condition data of the engine.
In a second aspect, the present invention provides the following technical solutions through an embodiment of the present invention:
a control apparatus of a variable compression ratio engine, comprising:
the determining module is used for determining an opening duration basic value and an opening time basic value of the control valve based on actual operation condition data of the engine;
the correction module corrects the basic value of the opening duration based on a compression ratio deviation correction coefficient and a water temperature correction coefficient, wherein the compression ratio deviation correction coefficient is determined based on the deviation of a set compression ratio and a detected actual compression ratio, and the water temperature correction coefficient is determined based on the water temperature of the engine;
and the control module is used for taking the minimum value of the corrected basic value of the opening duration and the preset maximum opening duration as a target opening duration, and controlling the opening of the control valve based on the basic value of the opening time of the control valve and the target opening duration to adjust the compression ratio of the engine if the target opening duration is greater than the preset minimum opening duration.
Preferably, the control module further includes:
the correction submodule is used for determining a start time correction value based on the opening duration of the control valve, and correcting the opening time basic value of the control valve based on the start time correction value to obtain a corrected opening time basic value;
the opening time obtaining submodule is used for obtaining the opening time of the control valve based on the corrected opening time basic value and the opening delay time of the control valve, wherein the opening delay time of the control valve is obtained based on the rotating speed of the engine;
the obtaining submodule is used for taking the maximum value from the obtained opening time and the preset minimum opening time of the control valve as the target opening time of the control valve;
and the control submodule is used for controlling the opening of the control valve based on the target opening time and the target opening duration.
In a third aspect, the present invention provides the following technical solutions through an embodiment of the present invention:
an engine control system, comprising: a hydraulic unit connected to the engine, a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method of the first aspect when executing the program to adjust the compression ratio of the engine by controlling the opening of the control valve.
One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:
the embodiment of the invention provides a control method and a control device of a variable compression ratio engine and an engine control system, wherein the method comprises the following steps: determining an opening duration basic value and an opening time basic value of a control valve based on actual operation condition data of an engine; correcting the basic value of the opening duration based on the compression ratio deviation correction coefficient and the water temperature correction coefficient; and then taking the minimum value of the corrected basic value of the opening duration and the preset maximum opening duration as the target opening duration, so that the maximum opening duration of the control valve is limited, the reverse motion of a compression ratio driving mechanism is effectively avoided, the correct regulation of the compression ratio is realized, and the problem of the out-of-control compression ratio is favorably inhibited. Under the condition that the target opening duration is longer than the preset minimum opening duration, the hydraulic mechanism is excited to control and adjust the compression ratio of the engine, so that the control on the compression ratio of the engine can be accurately realized, and the engine can safely and stably run in different working condition areas.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
Fig. 1 is a structural view of a variable compression ratio driven by a hydraulic mechanism provided in an embodiment of the invention;
FIG. 2 is a flowchart of a variable compression ratio engine control method provided by an embodiment of the present invention;
fig. 3 is a flowchart of control logic for controlling the opening time period of the valve according to an embodiment of the present invention;
fig. 4 is a flowchart of control logic for controlling the opening time of the valve according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a variable compression ratio engine control apparatus according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a variable compression ratio engine control apparatus according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of an engine control system according to an embodiment of the present invention.
Detailed Description
In the existing hydraulic mechanism, even if the hydraulic flow control valve is completely closed, the leakage phenomenon (inherent property) between the upper oil cavity and the lower oil cavity can not be avoided, and the error of the variable compression ratio mechanism and the delay characteristic of the opening and closing of the hydraulic flow control valve easily cause that the compression ratio can not be accurately controlled or even is out of control.
In view of this, the embodiments of the present application provide a method and an apparatus for controlling a variable compression ratio engine, and an engine control system, which can accurately implement control over a compression ratio of the engine, so that the engine can safely and stably operate in different operating condition areas.
In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.
The compression ratio, i.e., the degree to which the engine air-fuel mixture is compressed, is expressed by the ratio of the total volume of the cylinder before compression to the volume of the cylinder after compression (i.e., the volume of the combustion chamber). The compression ratio has a large relationship with the engine performance, and the higher the compression ratio, the greater the power of the engine.
The Control valve referred to herein refers to an element in a hydraulic transmission system or a hydraulic Control system for controlling hydraulic pressure, flow rate, and direction, and may be referred to as a CRCV (hydraulic flow Control valve) in this application.
In a first aspect, the control method of the variable compression ratio engine provided by the embodiment of the invention is applied to an engine control system, as shown in fig. 1, the system comprises a hydraulic mechanism 10, and a hydraulic flow control valve 101 in the hydraulic mechanism 10 is used for controlling the compression ratio of the engine.
Specifically, with a conventional non-variable compression ratio engine, the "top dead center" and "bottom dead center" positions at which the engine piston operates within the engine cylinder are fixed, so the compression ratio calculated therewith is a fixed value. The hydraulic mechanism designed as shown in fig. 1 is connected with the engine connecting rod 102 through the gear limiting mechanism 30, so that the positions of the 'top dead center 11' and the 'bottom dead center 12' of the engine piston 201 can be changed by changing the up-and-down displacement of the hydraulic driving connecting rod 103 and transmitting torque through the gear limiting mechanism 30, and then the compression ratio is changed.
The hydraulic drive connecting rod 103 is connected to a drive piston 104 disposed in the oil chamber, the drive piston 104 is disposed between an upper oil chamber 105 and a lower oil chamber 106, and the vertical displacement of the hydraulic drive connecting rod 103 can be adjusted by controlling the opening timing and the opening period of the hydraulic flow control valve 101. The hydraulic mechanism 10 here includes a hydraulic flow control valve 101 hydraulically driving a connecting rod 103, a driving piston 104, and an oil chamber (including an upper oil chamber 105 and a lower oil chamber 106). The combination of the hydraulic mechanism 10, the gear position limiting mechanism 30, and the engine link 102 is called a variable compression ratio mechanism.
As shown in fig. 2, the control method of the variable compression ratio engine includes the following steps S101 to S104.
And S101, determining an opening duration basic value and an opening time basic value of the control valve based on actual operation condition data of the engine.
It should be noted that the actual operating condition data may include: the engine control device comprises an operating mode of the engine, the rotating speed of the engine and an air intake quantity, wherein the operating mode comprises a combustion mode and a back-dragging (unburned) mode. In addition, the engine speed and the intake air amount can be obtained by detection and estimation, for example, the engine speed is obtained by looking at an engine speed meter, and the intake air amount is calculated through the results detected by the intake pressure sensor and the intake air flow sensor, which is not described in detail herein.
Of course, the actual operation condition data may include only the rotation speed of the engine and the intake air amount, so that the above process is: the step of determining the open time base value of the CRCV based on the engine speed and the intake air amount is performed.
In particular embodiments, the CRCV opening is driven indirectly by engine combustion pressure and inertia forces, such that the length of time the CRCV is opened is related to the actual operating conditions of the engine, and the length of time the CRCV is opened is different for different operating conditions. Specifically, as shown in fig. 3, a control table representing the CRCV opening time period basic value T0 at the rotation speed n and the estimated intake air amount m can be designed in ECU (Electronic control unit) software, so that the CRCV opening time period basic values at different rotation speeds and the estimated intake air amount can be accurately described.
The design process can be that CRCV opening time lengths under different rotating speeds and air inflow amounts are obtained through tests, data are recorded one by one, and a control table representing a rotating speed n and a basic value T0 of the required CRCV opening time length under an estimated air inflow amount m is established.
In an embodiment, before determining the opening duration basic value and the opening time basic value of the control valve based on the actual operation condition data of the engine, the method may further include:
when the detected resultant force direction required by the target compression ratio regulating quantity is the same as the actual resultant force direction of the current control window of the engine, sending an opening time and an opening duration command of a control valve, wherein the resultant force is the resultant force of combustion pressure, inertia force and pressure difference between an upper oil chamber and a lower oil chamber in an engine control system; and in response to the opening time and the opening duration command, executing the step of determining an opening duration base value of the control valve based on actual operation condition data of the engine.
The target compression ratio adjustment amount indicates an adjustment amount required when the current compression ratio state of the engine is adjusted to the desired target compression ratio.
The acquisition of the direction of the resultant force required by the target compression ratio adjustment amount comprises the following steps: and (3) carrying out stress analysis on the variable compression ratio mechanism based on the combustion pressure and the inertia force contained in the variable compression ratio mechanism and the pressure difference between the upper oil chamber and the lower oil chamber. Specifically, the combustion pressure received by the engine link and the inertial force by the hydraulic mechanism are combined into one set, and the vector sum is calculated and expressed as force F1; the pressure difference between the upper and lower oil chambers is equal to the oil pressure (e.g., 30bar) x the oil chamber force area difference (the difference between the areas contained in the upper and lower oil chambers), which is expressed as force F2. When the force F1 is greater than the force F2, i.e. the force applied to the engine link is greater than the force generated by the hydraulic mechanism, the engine link will drive the hydraulic mechanism to act, indicating that the engine is at a high compression ratio, and the compression ratio can be lowered. Otherwise, when the force F1 is less than the force F2, the hydraulic mechanism will drive the engine linkage to move, indicating that the engine is at a low compression ratio, at which point the compression ratio can be increased.
Specifically, when it is detected that the resultant force direction required by the target compression ratio adjustment amount is the same as the actual resultant force direction of the current control window of the engine, the CRCV opening time and opening duration command is issued, which may be understood as CRCV valve opening condition judgment, and the judgment process may include: dividing each Engine cycle into four fixed control windows (2 for increasing control windows and 2 for decreasing control windows) by EMS (Engine Management System) software, defined as: the window of increasing compression ratio can only be used to increase compression ratio and the window defined as decreasing compression ratio can only be used to decrease compression ratio. If the direction of the resultant force required for the target compression ratio adjustment (increase or decrease) is consistent with the actual resultant direction of the control window, then the control window is taken as the target control window, and the CRCV opening time and duration commands will be issued within the target control window. Instead, this control window must be abandoned, the next control window sought, the direction of the resultant force required to change the compression ratio being the same as the direction of the force of the control window, and then the corresponding CRCV opening time and opening duration commands issued.
Therefore, when it is detected that the engine needs to increase or decrease the compression ratio, the variable compression ratio mechanism will execute the step of determining the opening-period-base value of the control valve based on the engine speed and the intake air amount in response to the corresponding opening timing and opening-period commands, i.e., the CRCV opening timing and opening period commands, issued to the target control window.
And S102, correcting the basic value of the opening time length based on a compression ratio deviation correction coefficient and a water temperature correction coefficient, wherein the compression ratio deviation correction coefficient is determined based on the deviation of the set compression ratio and the detected actual compression ratio, and the water temperature correction coefficient is determined based on the water temperature of the engine.
In a specific embodiment, because a deviation exists between the target compression ratio of the engine and the detected actual compression ratio of the engine, and the deviation can affect the accurate acquisition of the basic value of the opening time length of the control valve, the deviation of the compression ratio needs to be corrected to obtain a more accurate basic value of the opening time length of the CRCV. The method has a feedback adjustment effect on the CRCV starting time based on the deviation, and generates a compression ratio deviation correction coefficient Pj. Specifically, as shown in fig. 3, it is possible to accurately describe the compression ratio deviation correction coefficients at different compression ratio deviations by designing a control table in the ECU software that characterizes the compression ratio deviation correction coefficient Pj generated at the compression ratio deviation.
Furthermore, since the temperature of the engine water is unstable, and the difference in the temperature of the engine water affects the viscosity of the liquid in the upper and lower chambers of the driving mechanism, and further affects the flow, the temperature of the engine water needs to be corrected. Specifically, as shown in fig. 3, a control table T representing the water temperature correction coefficient generated under the water temperature tewater can be designed in the ECU software, so that the water temperature correction coefficients under different water temperatures can be accurately described.
And correcting the basic value of the opening time length based on the compression ratio deviation correction coefficient and the water temperature correction coefficient, so that a more accurate CRCV opening time length reference value can be obtained.
Further, since there is a delay in the fluid flow of the hydraulic system and there is a mechanical delay in the CRCV opening and closing process itself, after correcting the opening time period base value based on the compression ratio deviation correction coefficient and the water temperature correction coefficient, it may further include: and correcting the corrected opening duration basic value based on the preset opening delay time and the preset closing delay time, wherein the opening delay time and the closing delay time are respectively determined based on the rotating speed of the engine and the air inflow.
It should be noted that, the modifying the modified basic value of the opening duration based on the preset opening delay time and the preset closing delay time may specifically include: the opening delay time is increased in the opening time of the control valve, and the closing delay time is decreased in the closing time of the control valve.
Specifically, as shown in FIG. 3, by designing a control table in the ECU software that characterizes the CRCV valve opening (closing) delay time t1(t2) at the rotation speed n and the predicted intake air amount m, the CRCV valve opening (closing) delay time at different rotation speeds and predicted intake air amounts can be accurately described.
And S103, taking the minimum value of the corrected basic value of the opening duration and the preset maximum opening duration as a target opening duration, and if the target opening duration is greater than the preset minimum opening duration, controlling the opening of the control valve based on the basic value of the opening time of the control valve and the target opening duration so as to adjust the compression ratio of the engine.
Specifically, because the CRCV has a maximum opening duration and a minimum opening duration, when the CRCV opening duration exceeds the two limits, the compression ratio driving mechanism may move in a reverse direction, which may cause an erroneous adjustment of the compression ratio and affect the actual working condition of the engine. Therefore, it is desirable to determine the CRCV maximum and minimum ON time periods.
As an alternative embodiment, the maximum opening period and the minimum opening period may be determined based on actual operating condition data of the engine. Specifically, as shown in FIG. 3, a control table representing the maximum (minimum) opening time period t3(t4) of the CRCV valve at the rotation speed n and the estimated air intake amount m can be designed in the ECU software, so that the maximum (minimum) opening time period of the CRCV valve at different rotation speeds and the estimated air intake amount can be accurately described.
In a specific embodiment, the minimum value is taken from the corrected basic value and the maximum opening time length of the opening time length to be used as the target opening time length, so that the CRCV target opening time length is always smaller than the maximum opening time length, and the reverse movement of the compression ratio driving mechanism is favorably avoided. If the target opening duration is longer than the minimum opening duration, the CRCV is controlled to be opened, the compression ratio driving mechanism is displaced, and the top dead center of the engine piston is changed, namely the compression ratio is changed. Conversely, the CRCV does not act, i.e., the compression ratio is not changed.
As an embodiment, the control valve may be a solenoid valve, and the control valve may be controlled by outputting an excitation signal to the control module.
As another alternative embodiment, controlling the control valve to open based on the opening timing base value of the control valve and the target opening duration may include:
determining a starting time correction value based on the opening duration of the control valve, and correcting the opening time basic value of the control valve based on the starting time correction value to obtain a corrected opening time basic value; obtaining the opening time of the control valve based on the corrected opening time basic value and the opening delay time of the control valve, wherein the opening delay time of the control valve is obtained based on the rotating speed of the engine; taking the maximum value from the obtained opening time and the preset minimum opening time of the control valve as the target opening time of the control valve; and controlling the opening of the control valve based on the target opening time and the target opening duration.
And the opening timing base value may be obtained based on the operating mode of the engine, the rotational speed of the engine, and the intake air amount. Wherein, because the engine has two kinds of mode: combustion and crank modes, due to their different operating characteristics, require a discussion of the CRCV valve opening timing base values in the combustion and crank modes, respectively.
Specifically, as shown in fig. 4, the opening time base value may be a control table based on CRCV opening time base values Topen1(Topen2) designed in ECU software in the combustion and tow-over modes for characterizing the rotation speed n and the estimated intake air amount m, respectively, so that the CRCV opening time base values in the combustion and tow-over modes for different rotation speeds and estimated intake air amounts can be accurately described. And according to the actual working mode of the engine, selecting the CRCV starting time base value in the corresponding control table by ECU software.
The opening time length of the CRCV valve has a certain correction effect on the opening time, and as shown in FIG. 4, a control table representing the CRCV valve opening time correction value ta under the CRCV valve opening time length T1 is designed in ECU software, so that the CRCV valve opening time correction value under different CRCV valve opening time lengths can be accurately described. The CRCV valve opening time length is the corrected opening time length, and the opening time correction value is determined according to the opening time length.
In addition, when acquiring the opening timing of the control valve, the influence of the CRCV valve opening delay time on the opening timing needs to be considered. Specifically, since the CRCV valve opening delay time is set to be later than the opening timing and the degree of the pull-back is different when the rotation speeds are different, the ECU software may consider the influence of the CRCV valve opening delay time on the opening timing at different rotation speeds, as shown in fig. 4.
Further, similar to the opening duration of the CRCV valve, there is also a minimum allowable opening time of the CRCV valve. Specifically, as shown in fig. 4, a control table representing the minimum opening time Tmin allowed by the CRCV valve at the rotation speed n and the estimated intake air amount m can be designed in the ECU software, so that the minimum opening time allowed by the CRCV valve at different rotation speeds and the estimated intake air amount can be accurately described. And (4) taking the larger value of the corrected CRCV valve opening time Topen3 and the CRCV valve minimum opening time Tmin as the final output value Topen of the CRCV valve opening time, namely the target opening time, so that the CRCV valve target opening time can be always greater than or equal to the minimum opening time, and more accurate control is realized.
And finally, controlling the accurate starting of the CRCV based on the obtained target starting time and the obtained target starting time length.
In summary, by the control method of the variable compression ratio engine provided by the embodiment of the invention, the control of the compression ratio of the engine can be realized more accurately without improving the hardware design of the existing hydraulic compression ratio control mechanism, so that the engine can operate safely and stably in different working condition areas. The control method solves the problems of serious knocking tendency and poor emission and drivability caused by poor compression ratio control precision. Meanwhile, potential safety hazards such as damage to an engine and the like caused by the fact that the compression ratio is out of control are avoided.
In a second aspect, based on the same inventive concept, the present embodiment provides a control apparatus of a variable compression ratio engine, as shown in fig. 5, comprising:
the determining module 501 is configured to determine an opening duration basic value and an opening time basic value of a control valve based on actual operation condition data of an engine;
a correction module 502 for correcting the opening duration basic value based on a compression ratio deviation correction coefficient determined based on a deviation between a set compression ratio and a detected actual compression ratio and a water temperature correction coefficient determined based on an engine water temperature;
and a control module 503, configured to take a minimum value between the modified basic value of the opening duration and a preset maximum opening duration as a target opening duration, and if the target opening duration is greater than the preset minimum opening duration, control the opening of the control valve based on the basic value of the opening time of the control valve and the target opening duration to adjust the compression ratio of the engine.
As an alternative embodiment, as shown in fig. 6, the control module 503 specifically includes:
the correction submodule 601 is configured to determine a start time correction value based on an opening duration of the control valve, and correct an opening time basic value of the control valve based on the start time correction value to obtain a corrected opening time basic value;
an opening time obtaining submodule 602 configured to obtain an opening time of the control valve based on the corrected opening time basic value and a control valve opening delay time, where the control valve opening delay time is obtained based on a rotation speed of the engine;
the obtaining submodule 603 is configured to take a maximum value from the obtained opening time and a preset minimum opening time of the control valve, and use the maximum value as a target opening time of the control valve;
a control sub-module 604 for controlling the opening of the control valve based on the target opening time and the target opening duration.
The above modules may be implemented by software codes, and in this case, the modules may be stored in a memory of the control device. The above modules may also be implemented by hardware, such as an integrated circuit chip.
The implementation principle and the technical effects of the control device of the variable compression ratio engine provided by the embodiment of the invention are the same as those of the method embodiment, and for the sake of brief description, the corresponding contents in the method embodiment can be referred to where the embodiment of the device is not mentioned.
In a third aspect, based on the same inventive concept, the present embodiment provides an engine control system 700, as shown in fig. 7, including: a hydraulic machine 704, a memory 701, a processor 702 and a computer program 703 stored in the memory and executable on the processor, wherein the hydraulic machine 704 is connected to an engine, wherein a control valve 705 in the hydraulic machine 704 is connected to the processor 702, and wherein the processor 702 implements the steps of the method according to any of the preceding first aspects when executing the program to adjust the compression ratio of the engine by controlling the opening of the control valve.
Since the engine control system described in the present embodiment is an engine control system used for implementing the method for controlling a variable compression ratio engine in the present embodiment, a person skilled in the art can understand the specific implementation of the engine control system of the present embodiment and various modifications thereof based on the control method described in the present embodiment, and therefore, how to implement the method in the present embodiment by the engine control system will not be described in detail herein. The engine control system adopted by the control method in the embodiment of the present application is within the protection scope of the present application as long as the engine control system is implemented by those skilled in the art.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A method of controlling a variable compression ratio engine, applied to an engine control system including a hydraulic mechanism in which a hydraulic flow control valve is used to control a compression ratio of the engine, the method comprising:
determining an opening duration basic value and an opening time basic value of the control valve based on actual operation condition data of the engine;
correcting the opening duration basic value based on a compression ratio deviation correction coefficient and a water temperature correction coefficient, wherein the compression ratio deviation correction coefficient is determined based on the deviation of a set compression ratio and a detected actual compression ratio, and the water temperature correction coefficient is determined based on the engine water temperature;
and taking the minimum value of the corrected basic value of the opening duration and the preset maximum opening duration as a target opening duration, and if the target opening duration is greater than the preset minimum opening duration, controlling the opening of the control valve based on the basic value of the opening time of the control valve and the target opening duration so as to adjust the compression ratio of the engine.
2. The method of claim 1, wherein said controlling the control valve opening based on the opening timing base value of the control valve and the target opening duration comprises:
determining a starting time correction value based on the opening duration of the control valve, and correcting the opening time basic value of the control valve based on the starting time correction value to obtain a corrected opening time basic value;
obtaining the opening time of the control valve based on the corrected opening time basic value and the control valve opening delay time, wherein the control valve opening delay time is obtained based on the rotating speed of the engine;
taking the maximum value from the obtained opening time and the preset minimum opening time of the control valve as the target opening time of the control valve;
and controlling the opening of the control valve based on the target opening time and the target opening duration.
3. The method of claim 1, wherein the actual operating condition data comprises:
the engine comprises an operating mode of the engine, a rotating speed of the engine and an air intake quantity, wherein the operating mode comprises a combustion mode and a dragging mode.
4. The method of claim 1, wherein after said modifying said open duration base value based on a compression ratio deviation correction factor and a water temperature correction factor, further comprising:
and correcting the corrected opening duration basic value based on a preset opening delay time and a preset closing delay time, wherein the opening delay time and the closing delay time are respectively determined based on the rotating speed of the engine and the air inflow.
5. The method of claim 4, wherein the modifying the modified on-duration base value based on the preset on-delay time and the preset off-delay time comprises:
increasing the opening delay time over an opening time of the control valve and decreasing the closing delay time over a closing time of the control valve.
6. The method of claim 1, wherein prior to determining the open time period base value for the control valve based on actual operating condition data of the engine, further comprising:
when the detected resultant force direction required by the target compression ratio adjustment amount is the same as the actual resultant force direction of the current control window of the engine, sending an opening time and an opening duration command of the control valve, wherein the resultant force is the resultant force of combustion pressure, inertia force and pressure difference between an upper oil chamber and a lower oil chamber in the engine control system;
and responding to the opening time and the opening duration command, and executing the step of determining the opening duration basic value of the control valve based on the actual operation condition data of the engine.
7. The method of claim 1, wherein the maximum on-time and the minimum on-time are determined based on actual operating condition data of the engine.
8. A control apparatus of a variable compression ratio engine, characterized by comprising:
the determining module is used for determining an opening duration basic value and an opening time basic value of the control valve based on actual operation condition data of the engine;
the correction module corrects the basic value of the opening duration based on a compression ratio deviation correction coefficient and a water temperature correction coefficient, wherein the compression ratio deviation correction coefficient is determined based on the deviation of a set compression ratio and a detected actual compression ratio, and the water temperature correction coefficient is determined based on the water temperature of the engine;
and the control module is used for taking the minimum value of the corrected basic value of the opening duration and the preset maximum opening duration as a target opening duration, and controlling the opening of the control valve based on the basic value of the opening time of the control valve and the target opening duration to adjust the compression ratio of the engine if the target opening duration is greater than the preset minimum opening duration.
9. The apparatus of claim 8, wherein the control module further comprises:
the correction submodule is used for determining a start time correction value based on the opening duration of the control valve, and correcting the opening time basic value of the control valve based on the start time correction value to obtain a corrected opening time basic value;
the opening time obtaining submodule is used for obtaining the opening time of the control valve based on the corrected opening time basic value and the opening delay time of the control valve, wherein the opening delay time of the control valve is obtained based on the rotating speed of the engine;
the obtaining submodule is used for taking the maximum value from the obtained opening time and the preset minimum opening time of the control valve as the target opening time of the control valve;
and the control submodule is used for controlling the opening of the control valve based on the target opening time and the target opening duration.
10. An engine control system, comprising: a hydraulic machine connected to an engine, a control valve in the hydraulic machine connected to the processor, a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the method according to any one of claims 1-7 when executing the program for adjusting the compression ratio of the engine by controlling the opening of the control valve.
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| US20040069254A1 (en) * | 2002-07-11 | 2004-04-15 | Nissan Motor Co., Ltd. | Compression ratio controlling apparatus and method for spark-ignited internal combustion engine |
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