WO2021197435A1

WO2021197435A1 - Compression ratio control method for variable compression ratio engine

Info

Publication number: WO2021197435A1
Application number: PCT/CN2021/084981
Authority: WO
Inventors: 王文宾; 邢化锋; 左坤峰; 张威; 陈利明; 宋东先; 杨乐; 代沙沙
Original assignee: 长城汽车股份有限公司
Priority date: 2020-04-01
Filing date: 2021-04-01
Publication date: 2021-10-07
Also published as: CN112664333A; CN112664333B

Abstract

Provided is a compression ratio control method for a variable compression ratio engine. The method comprises when the load of an engine rises, determining whether to enable an engine compression ratio adjustment function, if yes, obtaining, according to the current rotating speed and load of the engine, a required compression ratio basic value R1 corresponding to the current engine working condition, and obtaining, according to the current rotating speed and load change rate of the engine, a required compression ratio variation R2 of the engine, and further comprises determining whether to perform compression ratio switching in advance, if yes, adjusting the compression ratio of the engine to R3, wherein R3=R1+R2, otherwise, adjusting the compression ratio of the engine to R1. According to the compression ratio control method for a variable compression ratio engine, the compression ratio switching can be started in advance according to needs, so that the following performance of changes of an actual compression ratio and a required compression ratio in a compression ratio switching process can be guaranteed, thus the knocking problem caused by the lag of compression ratio adjustment can be avoided or reduced, and the operation smoothness, reliability, and emission of the engine can be improved.

Description

Variable compression ratio engine compression ratio control method

Cross-references to related applications

This disclosure requires the priority of a Chinese patent application filed with the Chinese Patent Office with an application number of 202010251722.X and titled "Variable compression ratio engine compression ratio control method" on April 1, 2020, the entire content of which is incorporated by reference In this disclosure.

Technical field

The present disclosure relates to an engine with a variable compression ratio, and more particularly, to a compression ratio control method used in the process of increasing engine load.

Background technique

With the continuous deterioration of environmental pollution and the continuous development of automobile energy saving and emission reduction technologies, passenger vehicle fuel consumption and emission regulations have become more and more stringent. How to improve automobile engine energy efficiency and improve emissions is a technical problem that internal combustion engine developers have been studying. There are many closely related parameters in the operation of internal combustion engines. These parameters complement each other and restrict each other. In order to achieve the best performance of the whole machine after the various parameters are compromised, variable parameters are a very important method. In the variable parameter design of the engine, the variable compression ratio technology (VCR) has won the approval of many automobile manufacturers because it can not only ensure the increase of engine torque and power, but also greatly reduce the fuel consumption in the partial load area and improve the emission. Pay attention to.

For a variable compression ratio engine, the required compression ratio DesR varies with engine operating conditions (speed, load). During the compression ratio switching process, the lag and accuracy of the position control response of the VCR mechanism directly affects the combustion and operation of the engine. Ride comfort and reliability. As shown in Figure 1, where R_h represents the high compression ratio zone, R_m represents the medium compression ratio zone, and R_l represents the low compression ratio zone. During the engine load rise process, if the engine load rises from L1 to L2, the required compression ratio DesR does not fall within R_h. If the load continues to rise, referring to the load change rate v_L1 from L1 to L2, it can be predicted that the time for L2 to rise to Lx is ΔL1/v_L1. When the engine load is greater than Lx, the required compression ratio DesR is within R_m (R_m<R_h), and the adjustment time of the variable compression ratio mechanism is t, as shown in Figure 2. If the required compression ratio becomes within R_m, then start the VCR mechanism adjustment, the actual compression ratio RealR>R_m in the adjustment process a→b, at this time RealR is inconsistent with the engine's required compression ratio R_m, which will affect the engine ignition efficiency, Fuel injection effect and combustion process, and there is a serious risk of knocking.

In the process of engine load drop, refer to Figure 1. If the engine load drops from L3 to L2, the demand compression ratio DesR will remain unchanged within R_m. If the load continues to drop, refer to the load change rate v_L2 from L3 to L4, and it can be predicted that L3 will drop to The time of Lx is ΔL2/v_L2. When the engine load is less than Lx, the required compression ratio DesR is within R_h (R_h>R_m), and the adjustment time of the variable compression ratio mechanism is t', as shown in Figure 3. If the required compression ratio becomes R_h, then start the VCR mechanism adjustment. In the adjustment process a'-b', the actual compression ratio RealR<R_h, at this time RealR and the engine's required compression ratio R_h are also inconsistent, which will affect the engine ignition efficiency, The fuel injection effect and the combustion process result in the deterioration of the engine's emission characteristics.

It can be seen from the above that in the process of engine load increase or decrease, the traditional target compression ratio calculation + actual position adjustment process, the VCR mechanism adjustment has a lag, which will inevitably affect the engine ignition efficiency, fuel injection effect and combustion process, and particularly It is the process of the engine load rising. Due to the knocking problem, the shortcomings are particularly obvious.

Public content

In view of this, the present disclosure aims to propose a variable compression ratio engine compression ratio control method, so as to avoid the knocking problem caused by the adjustment lag of the VCR mechanism to a certain extent during the engine load rise process.

In order to achieve the above objective, the technical solution of the present disclosure is achieved as follows:

A variable compression ratio engine compression ratio control method. The method includes the following control steps when the engine load increases:

a. Determine whether to enable the engine compression ratio adjustment function, if it is enabled, go to step b, otherwise control the engine to run at the default compression ratio;

b. According to the current engine speed and load, obtain the basic value R1 of the demand compression ratio corresponding to the current engine working condition;

c. According to the current engine speed and load change rate, obtain the engine demand compression ratio change R2;

d. Judge whether to switch the compression ratio in advance, if it is, go to step e, otherwise go to step f;

e. Switch the compression ratio and adjust the engine compression ratio to R3, where R3=R1+R2;

f. Switch the compression ratio and adjust the engine compression ratio to R1.

Further, in step a, the conditions for determining whether to enable the engine compression ratio adjustment function include but are not limited to: whether the compression ratio adjustment mechanism in the engine is malfunctioning, the engine temperature is not lower than the preset value, and the engine speed is not higher than the preset value And the speed change rate is lower than the preset value, and the engine load change rate is lower than the preset value.

Further, in the condition for determining whether to enable the engine compression ratio adjustment function, it is preferable to determine whether the compression ratio adjustment mechanism is faulty, and if the compression ratio adjustment mechanism fails, no other conditions are judged.

Further, in steps b and c, obtaining the basic value R1 of the demand compression ratio corresponding to the current engine operating condition and obtaining the change amount R2 of the demand compression ratio of the engine are all obtained by querying the corresponding preset MAP map.

Further, in step d, the judgment of whether to switch the compression ratio in advance includes:

d1. According to the engine load change rate v_L, and the difference ΔL between the current engine load and the corresponding compression ratio switching boundary point load, calculate the time t0 from the current state to the compression ratio adjustment, and t0=ΔL/v_L;

d2. Obtain the lag time t2 of the compression ratio adjustment mechanism according to the inherent response time t1 of the compression ratio adjustment mechanism in the engine, where t2=t1;

d3. Compare t0 and t2, if t0 is not greater than t2, switch the compression ratio in advance.

Further, in step d2, the lag time t2 also includes the change in response time Δt caused by the change in the rotation speed of the drive motor due to the change in the drive voltage of the drive motor in the compression ratio adjustment mechanism, and t2= t1+Δt.

Further, the default compression ratio is the minimum compression ratio position of the engine.

Further, in step e or f, the compression ratio switching process of the engine includes:

s1. Obtain the required position of the variable compression ratio adjustment mechanism according to the corresponding relationship between the engine compression ratio value to be adjusted and the position signal of the variable compression ratio adjustment mechanism in the engine;

s2. Based on the demand position of the variable compression ratio adjustment structure, and obtain the demand position of the drive motor according to the transmission ratio between the variable compression ratio adjustment mechanism and the drive motor of the mechanism;

s3. According to the difference between the current position of the drive motor and the required position of the drive motor, the drive motor is adjusted from the current position to the required position of the drive motor through closed-loop control, and changes with the position of the drive motor The variable compression ratio adjustment mechanism is driven by the drive motor to complete the compression ratio switching.

Further, the position signal of the variable compression ratio adjustment mechanism is obtained by including but not limited to a resolver angle position sensor, a Hall position sensor, and a potentiometer type position sensor.

Further, the manifestation of the engine load includes, but is not limited to, engine air intake, engine intake pressure, engine throttle position, and engine throttle opening.

Compared with the prior art, the present disclosure has the following advantages:

The compression ratio control method of the present disclosure is capable of performing compression ratio switching when the engine load needs to be switched in advance based on the judgment of whether to perform compression ratio switching under the condition that the engine compression ratio can be adjusted under the condition that the engine load is rising. The engine compression ratio is switched to the sum of the basic value of the demand compression ratio and the change of the demand compression ratio. Compared with the existing compression ratio control method, the compression ratio switching can be started earlier, which can ensure the actual compression ratio and the demand during the compression ratio switching process. The followability of the compression ratio change can avoid or reduce the knocking problem caused by the compression ratio adjustment lag, and can improve the engine running smoothness, reliability and emissions.

The above description is only an overview of the technical solutions of the present disclosure. In order to understand the technical means of the present disclosure more clearly, they can be implemented in accordance with the content of the specification, and in order to make the above and other objectives, features and advantages of the present disclosure more obvious and easy to understand. In the following, specific embodiments of the present disclosure are specifically cited.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present disclosure or related technologies, the following will briefly introduce the drawings that need to be used in the description of the embodiments or related technologies. Obviously, the drawings in the following description are of the present invention. For some of the disclosed embodiments, those of ordinary skill in the art can obtain other drawings based on these drawings without creative work.

The drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The exemplary embodiments and descriptions of the present disclosure are used to explain the present disclosure, and do not constitute an improper limitation of the present disclosure. In the attached picture:

Figure 1 shows the corresponding relationship between engine speed, load and engine compression ratio;

Figure 2 shows the compression ratio reduction switching process;

Figure 3 shows the switching process of increasing the compression ratio;

4 is a schematic diagram of a strategy of the compression ratio control method according to an embodiment of the disclosure;

FIG. 5 is a schematic diagram of MAP1 according to an embodiment of the disclosure;

FIG. 6 is a schematic diagram of MAP2 according to an embodiment of the disclosure;

Figure 7 is a schematic diagram showing the switching of the variable compression ratio mechanism of the engine;

FIG. 8 schematically shows a block diagram of a computing processing device for executing the method according to the present disclosure; and

Fig. 9 schematically shows a storage unit for holding or carrying program codes for implementing the method according to the present disclosure.

Specific embodiment

In order to make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments These are a part of the embodiments of the present disclosure, but not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present disclosure.

It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other if there is no conflict.

Hereinafter, the present disclosure will be described in detail with reference to the drawings and in conjunction with the embodiments.

This embodiment relates to a variable compression ratio engine compression ratio control method, which is specifically used for switching control of the compression ratio when the engine load increases, so as to achieve the compression ratio switching in advance through the control, thereby avoiding or reducing the compression ratio adjustment The knocking problem caused by lag can improve the smoothness, reliability and emissions of engine operation.

In terms of the overall control concept, the compression ratio control method of this embodiment includes the following control steps:

Step a: Determine whether to enable the engine compression ratio adjustment function, if enabled, go to step b, otherwise control the engine to run at the default compression ratio;

Step b: According to the current engine speed and load, obtain the basic value R1 of the demand compression ratio corresponding to the current engine working condition;

Step c: According to the current engine speed and load change rate, obtain the engine demand compression ratio change amount R2;

Step d: Determine whether to switch the compression ratio in advance, if it is, go to step e, otherwise go to step f;

Step e: Switch the compression ratio and adjust the engine compression ratio to R3, where R3=R1+R2;

Step f: Switch the compression ratio and adjust the engine compression ratio to R1.

Among them, in the above steps, combined with that shown in Figure 4, in step a, the engine compression ratio adjustment function is enabled to be judged. Specifically, if the compression ratio adjustment function is enabled, that is, the engine can currently perform compression ratio adjustment. Based on the specific control strategy, the bottom dead center position of the engine piston can be changed under the action of the variable compression ratio mechanism in the engine to realize the adjustment of the compression ratio. If the compression ratio adjustment function is not enabled, it means that the current engine cannot perform the adjustment operation of the compression ratio, and the engine can only run at the default compression ratio.

It should be noted that the default compression ratio when the above-mentioned compression ratio adjustment function is not enabled can be preset according to specific design requirements. However, in general, the default compression ratio can preferably be set to the minimum compression ratio of the engine Position, which makes the engine run at the minimum compression ratio. At this time, running at the minimum compression ratio can better adapt to various engine operating conditions, so as to fully ensure the safety of the engine. Moreover, for the variable compression ratio mechanism in the engine, it should also be designed to be able to automatically enter the minimum compression ratio position under the drive of the engine piston movement to enter the default compression when the mechanism fails and the compression ratio adjustment function cannot be enabled. Than state operation.

In this embodiment, for the judgment of whether to enable the engine compression ratio adjustment function, the judgment conditions include, but are not limited to, whether the compression ratio adjustment mechanism in the engine is malfunctioning, the engine temperature is not lower than the preset value, and the engine speed is not higher than the preset value. Value and the speed change rate is lower than the preset value, and the engine load change rate is lower than the preset value.

Among them, the failure of the compression ratio adjustment mechanism is, for example, the drive motor of the adjustment mechanism is blocked, the controller of the drive motor is faulty, the relevant sensor in the mechanism fails, or the communication between the adjustment mechanism and the engine control unit fails. Since the control of the compression ratio adjustment mechanism and other mechanisms in the engine are generally integrated in the engine control unit, that is, the engine ECU, the above-mentioned faults of the adjustment mechanism will generally be recognized by the engine ECU and deal with them accordingly. It belongs to the conventional technical means in the field of existing engines, and will not be repeated here.

In addition to the failure of the compression ratio adjustment mechanism, in addition to the engine temperature not lower than the preset value, it generally means that the engine should be in the state after the completion of the warm car when the compression ratio is adjusted, so as to avoid the low temperature and affect the engine performance. At this time, the above The preset value of the engine temperature may be, for example, 50°C. Of course, the preset temperature value can also be adjusted appropriately according to different design requirements. For the above-mentioned engine speed not higher than the preset value and speed change rate lower than the preset value, it specifically means that the operating speed of the engine should be within a reasonable range when the compression ratio is adjusted, and the speed should not be more urgent. Change, so as to ensure the smooth progress of the compression ratio adjustment function.

This embodiment is aimed at the preset value of rotation speed that is not higher than that, which can generally be the maximum rotation speed designed by the engine, and the rate of change of rotation speed that should be lower than that can be selected according to actual design requirements. In addition, for the engine load change rate should be lower than the preset value, its meaning is similar to the speed, that is, the engine load should be within a reasonable range when the compression ratio is adjusted to avoid sudden changes in engine load. This causes confusion in the compression ratio adjustment function. The preset value of the engine load change rate, which is the same as the speed change rate, can also be specifically selected according to actual design requirements.

It should be noted that in this embodiment, the judgment of enabling the compression ratio adjustment function, in addition to the above-mentioned ones, may also include other conditions. The designer can make a selection according to needs. Make restrictions. However, based on the above judgment conditions, when judging whether to enable the engine compression ratio adjustment function, it is preferable to first judge whether the compression ratio adjustment mechanism is malfunctioning, and if the compression ratio adjustment mechanism malfunctions, it will not be stopped. Judge other conditions to reduce operating power consumption.

In this embodiment, the required compression ratio base value R1 obtained in step b is specifically the compression ratio value that should be adopted under the current engine operating conditions of the engine, and this R1 is generally consistent with the current compression ratio value of the engine under stable engine operating conditions. The change in the demand compression ratio obtained in step c represents the change in the demand compression ratio in the change of the engine operating conditions based on the change trend of the current operating conditions of the engine. The basic value of the above demand compression ratio plus the amount of change will change according to the current working conditions, and when the compression ratio needs to be switched in advance, the compression ratio value that should be achieved, the compression ratio value that should be output can also achieve the compression ratio advancement Switch to avoid the lag problem caused by the existing compression ratio adjustment form.

In step b and step c, the acquisition of the basic value R1 of the demand compression ratio corresponding to the current engine operating condition and the acquisition of the change of the engine demand compression ratio R2 can both be obtained by querying the corresponding MAP map preset get. At this time, for the MAP map corresponding to the basic value of the demand compression ratio R1 and the MAP map corresponding to the engine demand compression ratio change R2, both can be obtained by calibrating the universal characteristics of the variable compression ratio engine, and at the same time the MAP map The data in can also be optimized through the compression ratio switching process test of the variable compression ratio engine.

In addition, as a specific example, this embodiment is directed to a variable compression ratio mechanism adopting a multi-link structure. The MAP map corresponding to the basic value R1 of the demand compression ratio and the MAP map corresponding to the change of the engine demand compression ratio R2 are respectively. As shown in Figure 5 and Figure 6. At this time, the variable compression ratio mechanism of the multi-link structure includes the eccentric shaft driven by the drive motor, and the mechanism form of the drive link, the adjustment link, and the execution link that are connected by articulated transmission in sequence, and for the convenience of MAP The description corresponding to the basic value of the demand compression ratio R1 can be called the MAP1 map, and the one corresponding to the change in the engine demand compression ratio R2 can be called the MAP2 map.

In this embodiment, on the premise that the variable compression ratio function is enabled, the determination of whether to switch the compression ratio in advance in step d specifically includes the following steps:

Step d1: According to the engine load change rate v_L, and the difference ΔL between the current engine load and the corresponding compression ratio switching boundary point load, calculate the time t0 from the current state to the occurrence of compression ratio adjustment, and t0=ΔL/v_L ；

Step d2: Obtain the lag time t2 of the compression ratio adjustment mechanism according to the inherent response time t1 of the compression ratio adjustment mechanism in the engine, where t2=t1;

Step d3: Compare t0 and t2, if t0 is not greater than t2, switch the compression ratio in advance.

Among them, the compression ratio switching boundary point load in the above step d1 can still be seen in Figure 1 for details. Taking the R_h area and the R_m area as an example, the switching boundary point load is also the high compression ratio area represented by R_h and the middle area represented by R_m. The load value on the vertical axis corresponding to the boundary between the compression ratio zones. For the calculation of the time t0 in step d1, the same can also be referred to the above description related to FIG. 1.

In this embodiment, the general lag time t2 is also the inherent response time t1 of the compression ratio adjustment mechanism itself, and the response time t1 can also be obtained through a test bench test after the components of the compression ratio adjustment mechanism are matched. However, since the existing variable compression ratio adjustment mechanism is generally driven by a drive motor, and the drive voltage used to drive the drive motor to rotate is often difficult to maintain at a constant value, this embodiment is a further preferred implementation form. Generally, the above-mentioned lag time t2 can also be added to the change Δt of the response time due to the change of the driving voltage of the driving motor, which is caused by the change of the rotation speed of the driving motor, at this time, that is, t2=t1+Δt.

The drive motor of the variable compression ratio mechanism changes the response time Δt of the mechanism due to the change in the drive voltage, which may be positive or negative depending on the drive voltage. In essence, the change Δt is also A correction amount of the response time of the variable compression ratio mechanism itself to ensure more accurate determination of the lag time. In addition, the change in response time Δt caused by the different drive voltages of the drive motors can be measured according to the corresponding relationship between the drive motor speed and the drive voltage and combined with the test bench of the variable compression ratio mechanism. It can be compiled into corresponding call data for the engine control unit to call when the compression ratio is switched.

In this embodiment, it should be noted that in step d3, for the determination condition that t0 is not greater than t2, it is generally preferred that t0 is equal to t2, that is, when t0 is equal to t2, the compression ratio is switched in advance. , Switch the engine compression ratio to R3. Only in this way can it be ensured that the actual compression ratio of the engine and the required compression ratio keep consistent follow, and the occurrence of knocking problems can be reduced or even avoided during the increase of engine load. In addition to making t0=t2, and starting to switch the compression ratio in advance when t0 is less than t2, it can also reduce the knocking phenomenon during load rise to a certain extent, but its effect is slightly worse than that of the preferred case of rise, and The greater the difference between t0 and t2, the worse the effect.

In addition, in the process of engine load drop, since the actual engine compression ratio increases from small to large, the actual value of the lagging compression ratio must be larger than the required compression ratio. There will be no knocking problems. Therefore, it is not necessary to use this embodiment when the load decreases. Control Method.

In this embodiment, after judging whether to switch the compression ratio in advance, the engine compression ratio switching process of step e or f is performed. At this time, whether it is step e or step f, the adjustment process when adjusting the compression ratio refers to FIG. 7 and includes the following steps:

Step s1: Obtain the required position of the variable compression ratio adjustment mechanism according to the corresponding relationship between the engine compression ratio value to be adjusted and the position signal of the variable compression ratio adjustment mechanism in the engine;

Step s2: based on the required position of the variable compression ratio adjustment structure, and obtain the required position of the drive motor according to the transmission ratio between the variable compression ratio adjustment mechanism and the drive motor of the mechanism;

Step s3: According to the difference between the current position of the drive motor and the demand position of the drive motor, the drive motor is adjusted from the current position to the demand position of the drive motor through closed-loop control, and the drive motor drives the adjustable position as the position of the drive motor changes. The variable compression ratio adjustment mechanism completes the compression ratio switching.

Among them, it should be noted that the position signal of the above variable compression ratio adjustment mechanism can be obtained by including but not limited to resolver angle position sensor, Hall position sensor, potentiometer type position sensor, etc. For the variable compression ratio mechanism The transmission form between the drive motor and the main body of the mechanism can be such as planetary gear transmission, harmonic reducer transmission, worm gear transmission and belt transmission. In addition, the main body of the variable compression ratio mechanism can be, for example, the aforementioned multi-link variable compression ratio mechanism including an eccentric shaft, a drive link, an adjustment link, and an execution link.

In addition, in this embodiment, the expression form of the engine load may include, but is not limited to, engine air intake, engine intake pressure, engine throttle position, and engine throttle opening. All of the above-mentioned forms can be used to express the engine load, and thus are applied to the control of the engine compression ratio of this embodiment.

The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in One place, or it can be distributed to multiple network units. Some or all of the modules may be selected according to actual needs to achieve the objectives of the solutions of the embodiments. Those of ordinary skill in the art can understand and implement it without creative work.

The various component embodiments of the present disclosure may be implemented by hardware, or by software modules running on one or more processors, or by a combination of them. Those skilled in the art should understand that a microprocessor or a digital signal processor (DSP) may be used in practice to implement some or all of the functions of some or all of the components in the computing processing device according to the embodiments of the present disclosure. The present disclosure can also be implemented as a device or device program (for example, a computer program and a computer program product) for executing part or all of the methods described herein. Such a program for realizing the present disclosure may be stored on a computer-readable medium, or may have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

For example, FIG. 8 shows a computing processing device that can implement the method according to the present disclosure. The computing processing device traditionally includes a processor 1010 and a computer program product in the form of a memory 1020 or a computer readable medium. The memory 1020 may be an electronic memory such as flash memory, EEPROM (Electrically Erasable Programmable Read Only Memory), EPROM, hard disk, or ROM. The memory 1020 has a storage space 1030 for executing program codes 1031 of any method steps in the above methods. For example, the storage space 1030 for program codes may include various program codes 1031 respectively used to implement various steps in the above method. These program codes can be read from or written into one or more computer program products. These computer program products include program code carriers such as hard disks, compact disks (CDs), memory cards, or floppy disks. Such a computer program product is usually a portable or fixed storage unit as described with reference to FIG. 9. The storage unit may have storage segments, storage spaces, etc. arranged similarly to the memory 1020 in the computing processing device of FIG. 8. The program code can be compressed in an appropriate form, for example. Generally, the storage unit includes computer-readable code 1031', that is, code that can be read by a processor such as 1010, which, when run by a computing processing device, causes the computing processing device to execute the method described above. The various steps.

The “one embodiment”, “an embodiment” or “one or more embodiments” referred to herein means that a specific feature, structure or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present disclosure. In addition, please note that the word examples "in one embodiment" here do not necessarily all refer to the same embodiment.

In the instructions provided here, a lot of specific details are explained. However, it can be understood that the embodiments of the present disclosure can be practiced without these specific details. In some instances, well-known methods, structures, and technologies are not shown in detail, so as not to obscure the understanding of this specification.

In the claims, any reference signs placed between parentheses should not be constructed as a limitation to the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of multiple such elements. The present disclosure can be realized by means of hardware including several different elements and by means of a suitably programmed computer. In the unit claims listing several devices, several of these devices may be embodied in the same hardware item. The use of the words first, second, and third, etc. do not indicate any order. These words can be interpreted as names.

The above descriptions are only the preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the present disclosure. Within the scope of protection.

Claims

A method for controlling the compression ratio of a variable compression ratio engine is characterized in that the method includes the following control steps when the engine load increases:

a. Determine whether to enable the engine compression ratio adjustment function, if it is enabled, go to step b, otherwise control the engine to run at the default compression ratio;

b. According to the current engine speed and load, obtain the basic value R1 of the demand compression ratio corresponding to the current engine working condition;

c. According to the current engine speed and load change rate, obtain the engine demand compression ratio change R2;

d. Judge whether to switch the compression ratio in advance, if it is, go to step e, otherwise go to step f;

e. Switch the compression ratio and adjust the engine compression ratio to R3, where R3=R1+R2;

f. Switch the compression ratio and adjust the engine compression ratio to R1.
The variable compression ratio engine compression ratio control method according to claim 1, characterized in that: in step a, the condition for determining whether to enable the engine compression ratio adjustment function includes, but is not limited to: whether the compression ratio adjustment mechanism in the engine is malfunctioning , The engine temperature is not lower than the preset value, the engine speed is not higher than the preset value and the speed change rate is lower than the preset value, and the engine load change rate is lower than the preset value.
The variable compression ratio engine compression ratio control method according to claim 2, characterized in that: in determining whether to enable the engine compression ratio adjustment function, it is preferable to determine whether the compression ratio adjustment mechanism is malfunctioning, and if the compression ratio Compared with the failure of the adjustment mechanism, no other conditions will be judged.
The variable compression ratio engine compression ratio control method according to claim 1, characterized in that: in steps b and c, the basic value R1 of the required compression ratio corresponding to the current engine operating condition is obtained, and the change amount R2 of the required compression ratio of the engine is obtained All are obtained by querying the preset corresponding MAP map.
The method for controlling the compression ratio of a variable compression ratio engine according to claim 1, wherein in step d, the determination of whether to switch the compression ratio in advance comprises:

d1. According to the engine load change rate v_L, and the difference ΔL between the current engine load and the corresponding compression ratio switching boundary point load, calculate the time t0 from the current state to the compression ratio adjustment, and t0=ΔL/v_L;

d2. Obtain the lag time t2 of the compression ratio adjustment mechanism according to the inherent response time t1 of the compression ratio adjustment mechanism in the engine, where t2=t1;

d3. Compare t0 and t2, if t0 is not greater than t2, switch the compression ratio in advance.
The variable compression ratio engine compression ratio control method according to claim 5, characterized in that: in step d2, the lag time t2 further includes a change in the drive voltage of the drive motor in the compression ratio adjustment mechanism, which is determined by The amount of change Δt in the response time generated by the change in the rotational speed of the drive motor, and t2=t1+Δt.
The variable compression ratio engine compression ratio control method according to claim 1, wherein the default compression ratio is the minimum compression ratio position of the engine.
The method for controlling the compression ratio of a variable compression ratio engine according to claim 1, wherein in step e or f, the compression ratio switching process of the engine includes:

s1. Obtain the required position of the variable compression ratio adjustment mechanism according to the corresponding relationship between the engine compression ratio value to be adjusted and the position signal of the variable compression ratio adjustment mechanism in the engine;

s2. Based on the demand position of the variable compression ratio adjustment structure, and obtain the demand position of the drive motor according to the transmission ratio between the variable compression ratio adjustment mechanism and the drive motor of the mechanism;

s3. According to the difference between the current position of the drive motor and the required position of the drive motor, the drive motor is adjusted from the current position to the required position of the drive motor through closed-loop control, and changes with the position of the drive motor The variable compression ratio adjustment mechanism is driven by the drive motor to complete the compression ratio switching.
The method for controlling the compression ratio of a variable compression ratio engine according to claim 8, wherein the position signal of the variable compression ratio adjustment mechanism includes but not limited to a resolver angle position sensor, a Hall position sensor, a potentiometer type The position sensor is obtained.
The method for controlling the compression ratio of a variable compression ratio engine according to any one of claims 1 to 9, wherein the manifestation of the engine load includes, but is not limited to, engine air intake, engine intake pressure, and engine throttle. Position and engine throttle opening.
A computing processing device, characterized in that it comprises:

A memory in which computer readable codes are stored; and

One or more processors, when the computer-readable code is executed by the one or more processors, the computing processing device executes the variable compression ratio engine according to any one of claims 1-10 Compression ratio control method.
A computer program comprising computer readable code, which when the computer readable code runs on a computing processing device, causes the computing processing device to execute the variable compression ratio according to any one of claims 1-10 Engine compression ratio control method.
A computer readable medium in which the computer program according to claim 12 is stored.