An engine compression ratio control method, device and storage medium

Abstract

The application discloses an engine compression ratio control method and device and a storage medium, wherein the method part comprises the following steps: determining an actual compression ratio of an engine and determining an expected compression ratio of the engine; determining a compression ratio evaluation parameter value of the engine according to the expected compression ratio and the actual compression ratio of the engine; determining whether the compression ratio of the engine needs to be adjusted according to the compression ratio evaluation parameter value; if the compression ratio of the engine needs to be adjusted, performing closed-loop adjustment on the compression ratio of the engine so that the actual compression ratio of the engine meets the requirements; in the application, the expected compression ratio and the actual compression ratio are compared and analyzed, the compression ratio evaluation parameter value is established to timely correct the engine compression ratio, the responsiveness of the compression ratio control is improved, the accurate control of the engine compression ratio is realized, the engine compression ratio can reach the best state, and therefore the engine can work efficiently.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and in particular to an engine compression ratio control method, device, and storage medium. Background Technology

[0002] As users' demands for vehicle power and fuel economy gradually increase, the performance requirements for engines, one of the most important components of a car, are also gradually rising. Currently, variable compression ratio (VCR) engines are widely used. By controlling the actual compression ratio, VCR engines can reduce fuel consumption and improve emissions, thereby enhancing both power and fuel economy.

[0003] In existing technologies, compression ratio control of variable compression ratio (VCR) engines typically involves dividing the engine's operating conditions into zones, each with a different operating compression ratio. During actual operation, the compression ratio is maintained at a specific value when the engine is operating within a particular zone; for example, a high compression ratio is used when the engine is operating under low load, and a low compression ratio is used when it is operating under high load. However, this method lacks precision in controlling the VCR engine's compression ratio, preventing it from reaching its optimal state and resulting in low engine efficiency. Summary of the Invention

[0004] This invention provides an engine compression ratio control method, device, and storage medium to solve the problem that the compression ratio control of variable compression ratio engines is not precise enough in the prior art, resulting in low engine efficiency.

[0005] A method for controlling the compression ratio of an engine is provided, comprising:

[0006] Determine the engine's actual compression ratio and the engine's desired compression ratio;

[0007] Based on the engine's desired compression ratio and actual compression ratio, determine the engine's compression ratio evaluation parameter value;

[0008] Based on the compression ratio evaluation parameter values, determine whether the engine compression ratio needs to be adjusted;

[0009] If it is necessary to adjust the engine's compression ratio, then the engine's compression ratio is adjusted in a closed loop to ensure that the engine's actual compression ratio meets the requirements.

[0010] Furthermore, the method for closed-loop adjustment of the engine's compression ratio also includes:

[0011] Monitor the rate of change of the actual compression ratio to determine whether the rate of change is within the preset rate range;

[0012] If the rate of change is within the preset rate range, the engine will be controlled to operate normally.

[0013] If the actual compression ratio is not within the preset range, the engine speed and torque will be limited until the engine stops running.

[0014] Furthermore, after determining the actual compression ratio of the engine, the method also includes:

[0015] Determine whether the actual compression ratio is within the preset compression ratio range;

[0016] If the actual compression ratio is within the preset compression ratio range, the engine will be controlled to operate normally.

[0017] If the actual compression ratio is not within the preset compression ratio range, the engine speed and torque will be limited until the engine stops running.

[0018] Furthermore, the actual compression ratio of the engine is determined, and the desired compression ratio of the engine is determined, including:

[0019] Determine the actual engine speed and actual load, and determine the control shaft phase of the compression ratio control shaft;

[0020] The actual compression ratio of the engine is determined based on the first preset data and the control shaft phase. The first preset data is the compression ratio of the engine at different control shaft phase values ​​during actual operation.

[0021] Based on the second preset data, the actual speed, and the actual load, the desired compression ratio of the engine is determined. The second preset data is the pre-calibrated optimal compression ratio of the engine under different operating conditions.

[0022] Furthermore, based on the compression ratio evaluation parameter values, it is determined whether the engine compression ratio needs to be adjusted, including:

[0023] When the compression ratio evaluation parameter value is positive, it is determined whether the engine compression ratio needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the first fluctuation threshold.

[0024] When the compression ratio evaluation parameter value is negative, it is determined whether the engine compression ratio needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the second fluctuation threshold.

[0025] Furthermore, the engine's compression ratio is controlled by a compression ratio hydraulic system, which includes hydraulic solenoid valves to perform closed-loop regulation of the engine's compression ratio so that the engine's actual compression ratio meets the requirements, including:

[0026] Based on the third preset data and the desired compression ratio, the target duty cycle of the hydraulic solenoid valve is determined. The third preset data includes different engine compression ratios and the corresponding hydraulic solenoid valve duty cycles.

[0027] The hydraulic solenoid valve is controlled according to the target duty cycle to perform PID control on the engine's compression ratio.

[0028] In the PID control process, it is determined whether the compression ratio difference between the desired compression ratio and the actual compression ratio meets the preset conditions.

[0029] If the compression ratio difference meets the preset conditions, then the actual compression ratio of the engine is determined to meet the requirements.

[0030] Furthermore, before determining the actual compression ratio of the engine, the method also includes:

[0031] Determine if there is a malfunction in the compression ratio hydraulic system;

[0032] If the compression ratio hydraulic system is functioning correctly, the actual compression ratio of the engine is obtained.

[0033] If the compression ratio hydraulic system malfunctions, determine whether the compression ratio hydraulic system has a physical locking function;

[0034] If the compression ratio hydraulic system has a physical lock-up function, then when the user has a need to use the vehicle, the compression ratio of the engine is controlled according to the fourth preset data, which is the compression ratio of the engine under different operating conditions in the fault mode of the fourth preset data.

[0035] An engine compression ratio control device is provided, comprising:

[0036] The first determining module is used to determine the actual compression ratio of the engine and the desired compression ratio of the engine.

[0037] The second determining module is used to determine the engine's compression ratio evaluation parameter value based on the engine's expected compression ratio and actual compression ratio.

[0038] The third determining module is used to determine whether the engine's compression ratio needs to be adjusted based on the compression ratio evaluation parameter value.

[0039] The adjustment module is used to perform closed-loop adjustment of the engine's compression ratio if it is necessary to adjust the engine's compression ratio, so that the actual compression ratio of the engine meets the requirements.

[0040] An engine compression ratio control device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the engine compression ratio control method described above.

[0041] A readable storage medium is provided, which stores a computer program that, when executed by a processor, implements the steps of the above-described engine compression ratio control method.

[0042] In one scheme provided by the aforementioned engine compression ratio control method, device, and storage medium, the actual compression ratio of the engine is determined, and the desired compression ratio of the engine is also determined. Then, based on the desired and actual compression ratios, an engine compression ratio evaluation parameter value is determined. Based on the compression ratio evaluation parameter value, it is determined whether the engine compression ratio needs adjustment. If adjustment is needed, closed-loop adjustment is performed to ensure the actual compression ratio meets the requirements. In this invention, by comparing and analyzing the desired and actual compression ratios, a compression ratio evaluation parameter value is established to promptly correct the engine compression ratio, improving the responsiveness of compression ratio control and achieving precise control of the engine compression ratio. This allows the engine compression ratio to reach its optimal state, thereby ensuring efficient engine operation. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the engine compression ratio control system in one embodiment of the present invention;

[0045] Figure 2 This is a schematic flowchart of an engine compression ratio control method according to an embodiment of the present invention;

[0046] Figure 3 This is another schematic flowchart of the engine compression ratio control method in one embodiment of the present invention;

[0047] Figure 4 yes Figure 2 A schematic diagram of the implementation process of step S40;

[0048] Figure 5 This is a schematic diagram of an engine compression ratio control device in one embodiment of the present invention;

[0049] Figure 6 This is another structural schematic diagram of the engine compression ratio control device in one embodiment of the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] The engine compression ratio control method provided in this embodiment of the invention can be applied to, for example... Figure 1 The engine compression ratio control system shown includes a compression ratio hydraulic system 1 and an engine compression ratio control device 2. The compression ratio hydraulic system 1 communicates with the engine compression ratio control device 2 via a vehicle bus.

[0052] In this embodiment, the compression ratio hydraulic system 1 includes an engine 11, a hydraulic solenoid valve 12, a hydraulic limiter 13, a compression ratio control shaft 14, and a multi-link structure 15. The engine 11 is a variable compression ratio engine; the hydraulic solenoid valve 13 is used to adjust and maintain the compression ratio of the engine 11; the hydraulic solenoid valve 12 is used to distribute flow to the hydraulic limiter 13; the compression ratio control shaft 14 is an actuator used to adjust the compression ratio of the engine 11 in conjunction with the hydraulic limiter 13, and the compression ratio control shaft 14 adjusts the compression ratio of the engine 11 through the multi-link structure 15; the multi-link structure 15 is part of the engine 11 and consists of a multi-link and a crankshaft. The engine compression ratio control device 2 can be an electronic control unit (ECU) on the engine 11. In other embodiments, the engine compression ratio control device 2 can also be other control devices on the vehicle, which will not be elaborated here.

[0053] After the vehicle is powered on, the ECU determines the engine's actual compression ratio and its desired compression ratio. Then, based on these two values, it determines the engine's compression ratio evaluation parameter. Next, based on this evaluation parameter, it determines whether compression ratio adjustment is needed. If adjustment is required, closed-loop control is implemented to ensure the actual compression ratio meets the requirements. By comparing and analyzing the desired and actual compression ratios, the ECU establishes the compression ratio evaluation parameter to promptly correct the engine's compression ratio, improving the responsiveness of compression ratio control and achieving precise control. This allows the engine's compression ratio to reach its optimal state, enabling stable and efficient engine operation, thereby improving both power and fuel economy.

[0054] In this embodiment, the engine compression ratio control system includes a compression ratio hydraulic system and an engine compression ratio control device. The compression ratio hydraulic system includes an engine, a hydraulic solenoid valve, a hydraulic limiter, a compression ratio control shaft, and a multi-link structure. These are all illustrative examples only. In other embodiments, the engine compression ratio control system and the compression ratio hydraulic system may also include other structures, such as a phase sensor, which will not be described in detail here.

[0055] In one embodiment, such as Figure 2 As shown, an engine compression ratio control method is provided, which is applied to... Figure 1 Taking the engine compression ratio control device as an example, the explanation includes the following steps:

[0056] S10: Determine the actual compression ratio of the engine and the desired compression ratio of the engine.

[0057] After the vehicle is powered on, the engine compression ratio control unit (ECU) needs to monitor the actual compression ratio of the engine in the compression ratio hydraulic system in real time to determine the actual compression ratio of the engine. At the same time, it also needs to determine the desired compression ratio of the engine so as to adjust and control the engine compression ratio according to the relationship between the actual compression ratio and the desired compression ratio.

[0058] Since the actual compression ratio of the engine cannot be directly obtained, this compression ratio hydraulic system adjusts it by regulating the phase of the compression ratio control shaft. This changes the phase between the compression ratio control shaft and the engine's multi-link structure, thus regulating the engine's compression ratio. There is a one-to-one correspondence between the phase of the compression ratio control shaft (control shaft phase) and the engine's compression ratio, and also a one-to-one correspondence between the phase of the multi-link structure and the engine's compression ratio. The actual compression ratio of the engine can be determined by the phase of the control shaft or the phase of the multi-link structure. Therefore, in this embodiment, a phase sensor can be installed at the compression ratio control shaft or the multi-link structure. When the vehicle is powered on, the ECU powers on and begins to collect the phase data of the control shaft or the multi-link structure to determine the engine's actual compression ratio.

[0059] The desired compression ratio of the engine is the optimal compression ratio of the engine under the current operating conditions. The desired compression ratio of the engine is determined by the current operating conditions of the engine.

[0060] S20: Determine the engine compression ratio evaluation parameter value based on the engine's expected compression ratio and actual compression ratio.

[0061] After determining the engine's actual compression ratio and its desired compression ratio, it is necessary to determine the engine's compression ratio evaluation parameter value based on the engine's desired and actual compression ratios.

[0062] In this embodiment, to facilitate calculation, reduce the computational load on the ECU, and improve the compression ratio response speed, the engine's compression ratio evaluation parameter value can be the difference between the engine's expected compression ratio and the actual compression ratio. The calculation formula is as follows:

[0063] Δε=ε t -ε c ;

[0064] Where Δε is the engine compression ratio evaluation parameter value, ε t ε represents the desired compression ratio of the engine. c This is the engine's actual compression ratio.

[0065] In this embodiment, the engine compression ratio evaluation parameter value is the difference between the engine's expected compression ratio and its actual compression ratio. This is merely an illustrative example; in other embodiments, the engine compression ratio evaluation parameter value can be determined in other ways. For example, the average value of the compression ratio difference between the engine's expected and actual compression ratios within a preset period can be taken as the engine compression ratio evaluation parameter value to improve its accuracy and reduce the frequency of adjustments to the engine's compression ratio. Alternatively, after the vehicle is powered on, the compression ratio difference between the engine's expected and actual compression ratios can be integrated, and the integration result can be used as the compression ratio evaluation parameter value to further improve its accuracy.

[0066] Since the actual compression ratio of the engine changes dynamically in real time, and the desired compression ratio of the engine changes with the engine's real-time operating conditions, the engine's compression ratio evaluation parameter value is also a real-time dynamically changing data.

[0067] S30: Determine whether the engine compression ratio needs to be adjusted based on the compression ratio evaluation parameter value.

[0068] After determining the engine's compression ratio evaluation parameter value based on the engine's expected compression ratio and actual compression ratio, the actual compression ratio is judged based on the magnitude of the compression ratio evaluation parameter value to determine whether the engine's compression ratio needs to be adjusted.

[0069] After determining whether the engine compression ratio needs to be adjusted based on the compression ratio evaluation parameter value, if it is determined that the engine compression ratio does not need to be adjusted, the compression ratio hydraulic system is controlled to enter the normal mode to respond to the normal power demand of the vehicle.

[0070] S40: If it is necessary to adjust the engine compression ratio, the engine compression ratio will be adjusted in a closed loop to ensure that the actual compression ratio of the engine meets the requirements.

[0071] After determining whether the engine compression ratio needs to be adjusted based on the compression ratio evaluation parameter value, if it is determined that the engine compression ratio needs to be adjusted, it means that the difference between the current engine's actual compression and the desired compression ratio is too large, and the current engine's actual compression does not meet the requirements. In order to ensure the vehicle's power and efficiency, it is necessary to perform closed-loop adjustment of the engine's compression ratio through the compression ratio hydraulic system so that the engine's actual compression ratio meets the requirements.

[0072] The closed-loop adjustment of the engine's compression ratio requires repeating steps S10-S30. During the adjustment process, the desired and actual compression ratios of the engine need to be acquired in real time to determine the real-time compression ratio evaluation parameter value. Then, based on the real-time compression ratio evaluation parameter value, a cyclic judgment is made to determine whether the engine's compression ratio needs to be adjusted. If the engine's compression ratio needs to be adjusted, the duty cycle of the hydraulic solenoid valve is changed to change the position of the hydraulic limiter, thereby changing the phase of the compression ratio control shaft that cooperates with the hydraulic limiter, and thus changing the phase of the multi-link structure to achieve the adjustment of the engine's compression ratio until the adjusted actual compression ratio meets the requirements.

[0073] In this embodiment, the optimal compression ratio (desired compression ratio) of the engine under the current operating conditions is determined, and then compared with the actual compression ratio of the engine measured in the experiment. A compression ratio evaluation parameter value is established to correct the engine compression ratio in a timely manner. The changes in the actual compression ratio are monitored based on the iterative analysis of the compression ratio evaluation parameter value, and the actual compression ratio is controlled and adjusted in a closed loop based on the hydraulic solenoid valve. This improves the responsiveness of the compression ratio control and achieves precise and efficient control of the engine compression ratio.

[0074] In this embodiment, the actual compression ratio of the engine is used to determine the desired compression ratio. Then, based on the desired and actual compression ratios, the engine compression ratio evaluation parameter value is determined. Next, based on the compression ratio evaluation parameter value, it is determined whether the engine compression ratio needs adjustment. If adjustment is required, closed-loop adjustment is performed to ensure the actual compression ratio meets the requirements. By comparing and analyzing the desired and actual compression ratios, a compression ratio evaluation parameter value is established to promptly correct the engine compression ratio, improving the responsiveness of compression ratio control and achieving precise control of the engine compression ratio. This allows the engine compression ratio to reach its optimal state, enabling stable and efficient engine operation, thereby improving the engine's power and fuel economy.

[0075] In one embodiment, step S10, namely determining the actual compression ratio of the engine and determining the desired compression ratio of the engine, specifically includes the following steps:

[0076] S11: Determine the actual engine speed and actual load, and determine the control shaft phase of the compression ratio control shaft.

[0077] After the vehicle is powered on, the ECU needs to determine the engine's actual speed and actual load, and determine the control shaft phase of the compression ratio control shaft in the compression ratio hydraulic system.

[0078] In this embodiment, the ECU includes a function to monitor the phase of the compression ratio control shaft, the actual speed of the engine, and the actual load. After the ECU is powered on, it can monitor and collect the control shaft phase of the compression ratio control shaft, the actual speed of the engine, and the actual load in real time.

[0079] S12: Determine the actual compression ratio of the engine based on the first preset data and the control shaft phase.

[0080] After the vehicle is powered on, the ECU needs to acquire the first preset data. This first preset data represents the engine's compression ratio at different control shaft phase values ​​during actual operation. This data is calibrated based on the design structure of the compression ratio hydraulic system. When designing the compression ratio hydraulic system, the engine's actual compression ratio changes with the control shaft phase, with each control shaft phase value corresponding to a specific engine compression ratio. To ensure data accuracy, after engine assembly, a compression ratio test can be performed to obtain the engine's compression ratio at different control shaft phase values, thereby calibrating the pre-calibrated first preset data. The first preset data includes the engine's compression ratio at different control shaft phase values, with each control shaft phase value corresponding to a specific engine compression ratio.

[0081] After determining the control shaft phase of the compression ratio control shaft in the compression ratio hydraulic system, the actual compression ratio of the engine is determined based on the first preset data and the control shaft phase.

[0082] After determining the control axis phase of the compression ratio control axis, the engine compression ratio corresponding to the control axis phase is queried from the first preset data and used as the engine compression ratio. This method is fast, simple, and highly accurate. In this embodiment, since the engine compression ratio can be actively controlled through the compression ratio control axis, using the control axis phase to determine the engine compression ratio has higher accuracy.

[0083] S13: Determine the desired compression ratio of the engine based on the second preset data, the actual speed, and the actual load.

[0084] After the vehicle is powered on, the ECU needs to acquire a second set of preset data. This second set of preset data is a pre-calibrated optimal compression ratio expected by the engine under different operating conditions (different speeds and loads). The second set of preset data is obtained by conducting compression ratio tests on the engine under different operating conditions to ensure data accuracy. Since the engine has different optimal compression ratios at different speeds and loads, the expected compression ratio can be determined by identifying the engine's actual speed and load, based on the second set of preset data, the actual speed, and the actual load. The optimal compression ratio corresponding to both the actual speed and actual load is then found within the second set of preset data and used as the engine's expected compression ratio.

[0085] In other embodiments, after obtaining the first preset data and the second preset data, the first preset data and the second preset data can be made into a Map, namely the first Map (Map θ ), Second Map (Map ε Then Map θ Map ε It is built into the ECU's memory. After obtaining the actual engine speed and actual load, and determining the control shaft phase of the compression ratio control shaft, it directly uses the control shaft phase in the Map... θ Find the actual compression ratio and directly use it in the Map based on the actual speed and actual load. ε The desired compression ratio can be found in the middle, reducing the amount of data processing. It is convenient and quick to determine the data, thereby improving the response speed of subsequent compression ratio adjustment.

[0086] In this embodiment, the actual engine speed and actual load are determined, and the control shaft phase of the compression ratio control shaft in the compression ratio hydraulic system is determined. Then, based on the first preset data and the control shaft phase, the actual compression ratio of the engine is determined. At the same time, based on the second preset data, the actual speed, and the actual load, the desired compression ratio of the engine is determined. This clarifies the specific process of determining the actual compression ratio of the engine in the compression ratio hydraulic system and the desired compression ratio of the engine. The data processing is fast and the accuracy of the data is guaranteed.

[0087] In one embodiment, such as Figure 3 As shown, after step S10, i.e. after determining the actual compression ratio of the engine, the method further includes the following steps:

[0088] S101: Determine whether the actual compression ratio of the engine is within the preset compression ratio range.

[0089] After determining the actual compression ratio of the engine in the compression ratio hydraulic system, it is necessary to monitor the actual compression ratio of the engine so as to limit the engine to a certain extent when the actual compression ratio of the engine exceeds the safe compression ratio range, thereby ensuring driving safety.

[0090] After determining the actual compression ratio of the engine in the compression ratio hydraulic system, it is necessary to determine whether the actual compression ratio of the engine is within the preset compression ratio range. The preset compression ratio range is a pre-calibrated, permissible range of engine compression ratios. The maximum value of the preset compression ratio range is the upper limit of the permissible engine compression ratio, and the minimum value of the preset compression ratio range is the lower limit of the permissible engine compression ratio.

[0091] To ensure vehicle driving safety, it is necessary to control the engine's actual compression ratio within a preset compression ratio range. This is determined by the following methods:

[0092] Determine whether the engine's actual compression ratio is greater than the engine's upper limit value ε. cmax And determine whether the actual compression ratio of the engine is less than the lower limit value ε of the engine compression ratio. cmin If the engine's actual compression ratio is less than or equal to the upper limit and greater than or equal to the lower limit, then the engine's actual compression ratio is within the preset range, indicating that the engine's actual compression ratio is normal and controllable. The engine will then be controlled according to normal control logic, allowing it to operate normally. If the engine's actual compression ratio is greater than the upper limit or less than the lower limit, then the engine's actual compression ratio is not within the preset range, indicating an abnormality in the engine's actual compression ratio. The compression ratio hydraulic system may be malfunctioning. To ensure driving safety, the engine needs to be restricted to stop, and the vehicle must cease operation.

[0093] S101: If the actual compression ratio is within the preset compression ratio range, control the engine to operate normally.

[0094] After determining whether the engine's actual compression ratio is within the preset compression ratio range, if the actual compression ratio is within the preset compression ratio range, it indicates that the engine's actual compression ratio is normal and controllable. The engine is then controlled according to the normal control logic to ensure normal engine operation.

[0095] S101: If the actual compression ratio is not within the preset compression ratio range, the engine speed and torque will be limited until the engine stops running.

[0096] After determining whether the engine's actual compression ratio is within the preset range, if the actual compression ratio is not within the preset range, it indicates an abnormality in the engine's actual compression ratio, and the compression ratio hydraulic system may be malfunctioning. To avoid engine damage and ensure driving safety, it is necessary to limit the engine speed and torque until the engine stops running, thereby safely stopping the vehicle. Simultaneously, it is also necessary to control the engine to issue an alarm so that the user is promptly informed of the actual compression ratio status and can take appropriate action.

[0097] In this embodiment, after determining the actual compression ratio of the engine, it is determined whether the actual compression ratio is within a preset compression ratio range. If the actual compression ratio is within the preset compression ratio range, the engine is controlled to operate normally; if the actual compression ratio is not within the preset compression ratio range, the engine speed and torque are limited until the engine stops operating. By monitoring the actual compression ratio of the engine in real time during engine operation, the engine speed and torque can be limited in a timely manner when an abnormality occurs in the actual compression ratio, so as to stop the engine and ensure engine safety and driving safety.

[0098] In one embodiment, step S30, which determines whether the engine needs to adjust its compression ratio based on the compression ratio evaluation parameter value, specifically includes the following steps:

[0099] S31: When the compression ratio evaluation parameter value is positive, determine whether the engine compression ratio needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the first fluctuation threshold.

[0100] In this embodiment, the compression ratio evaluation parameter value of the engine is taken as the compression ratio difference between the engine's expected compression ratio and the actual compression ratio, that is, Δε = ε t -ε c For example, this will reduce the amount of data processing required for subsequent calculations.

[0101] After determining the engine's compression ratio evaluation parameter value, the next step is to determine whether the engine's compression ratio evaluation parameter value is greater than 0, i.e., whether the engine's expected compression ratio is greater than the actual compression ratio. If the engine's compression ratio evaluation parameter value is greater than 0, the value is positive, indicating that the engine's expected compression ratio is greater than the actual compression ratio; if the value is less than 0, the value is negative, indicating that the engine's expected compression ratio is less than the actual compression ratio. Different judgment logic is executed based on different determination results.

[0102] When the engine's compression ratio evaluation parameter is positive (greater than 0), it indicates that the engine's expected compression ratio is greater than the actual compression ratio. In this case, it is necessary to determine whether the engine's compression ratio needs adjustment based on the magnitude of the compression ratio evaluation parameter and the first fluctuation threshold. The first fluctuation threshold is a pre-calibrated lower limit for engine compression ratio fluctuation. This threshold is obtained based on engine compression ratio test results and represents the minimum permissible difference between the engine's expected and actual compression ratios.

[0103] Based on the engine's compression ratio evaluation parameter value and the magnitude of the first fluctuation threshold, determine whether the engine's compression ratio needs adjustment, including: obtaining the first fluctuation threshold Δε. llimitDetermine whether the compression ratio evaluation parameter value is greater than the first fluctuation threshold; if the compression ratio evaluation parameter value is less than or equal to the first fluctuation threshold, i.e., Δε≤Δε llimit If the compression ratio evaluation parameter value Δε meets the fluctuation requirement, it means that the difference between the engine's expected compression ratio and the actual compression ratio is within the allowable deviation, and therefore no compression ratio adjustment is needed, and the hydraulic solenoid valve does not need to be replaced. If the compression ratio evaluation parameter value is greater than the first fluctuation threshold, i.e., Δε > Δε llimit This indicates that the compression ratio evaluation parameter value Δε does not meet the fluctuation requirements. It is considered that the compression ratio difference between the engine's expected compression ratio and the actual compression ratio is too small. Therefore, the compression ratio of the engine needs to be adjusted, which means controlling the hydraulic solenoid valve to increase the engine's actual compression ratio.

[0104] S31: When the compression ratio evaluation parameter value is negative, determine whether the engine compression ratio needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the second fluctuation threshold.

[0105] When the engine's compression ratio evaluation parameter is negative (less than 0), it indicates that the engine's expected compression ratio is less than the actual compression ratio. In this case, it is necessary to determine whether the engine's compression ratio needs adjustment based on the value of the compression ratio evaluation parameter and the magnitude of the second fluctuation threshold. The second fluctuation threshold is a pre-calibrated upper limit for engine compression ratio fluctuation. It is obtained based on engine compression ratio test results and represents the maximum permissible difference between the engine's expected and actual compression ratios.

[0106] Based on the engine's compression ratio evaluation parameter value and the magnitude of the second fluctuation threshold, determine whether the engine's compression ratio needs adjustment, including: obtaining the second fluctuation threshold Δε. ulimit Determine whether the absolute value of the compression ratio evaluation parameter is greater than the first fluctuation threshold; if the absolute value of the compression ratio evaluation parameter is less than or equal to the first fluctuation threshold, i.e., |Δε|≤Δε ulimit If the compression ratio evaluation parameter value Δε meets the fluctuation requirement, it means that the difference between the engine's expected compression ratio and the actual compression ratio is within the allowable deviation, and therefore no compression ratio adjustment is needed, and the hydraulic solenoid valve does not need to be replaced. If the absolute value of the compression ratio evaluation parameter value is greater than the second fluctuation threshold, i.e., |Δε|>Δε ulimit This indicates that the compression ratio evaluation parameter value Δε does not meet the fluctuation requirements. It is considered that the difference between the engine's expected compression ratio and the actual compression ratio is too large. Therefore, the compression ratio of the engine needs to be adjusted, which means that the hydraulic solenoid valve needs to be controlled to reduce the engine's actual compression ratio.

[0107] In this embodiment, when the compression ratio evaluation parameter value is positive, it is determined whether the engine compression ratio needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the first fluctuation threshold; when the compression ratio evaluation parameter value is negative, it is determined whether the engine compression ratio needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the second fluctuation threshold. This clarifies the specific process of determining whether the engine compression ratio needs to be adjusted based on the compression ratio evaluation parameter value. By using the compression ratio evaluation parameter value to determine whether the actual compression ratio of the engine needs to be adjusted, and by adopting different evaluation thresholds for different compression ratio evaluation parameter values, the accuracy of the determination result is ensured, thereby ensuring the precision of subsequent compressor control of the engine.

[0108] In one embodiment, in step S40, the compression ratio of the engine is controlled by a compression ratio hydraulic system, which includes a hydraulic solenoid valve to perform closed-loop adjustment of the engine's compression ratio so that the actual compression ratio of the engine meets the requirements. Specifically, this includes the following steps:

[0109] S41: Determine the target duty cycle of the hydraulic solenoid valve based on the third preset data and the desired compression ratio.

[0110] After determining the need for engine compression ratio adjustment based on the compression ratio evaluation parameters, it is necessary to obtain the third preset data. This third preset data is data pre-calibrated according to the hydraulic system structure, and includes different engine compression ratios and the corresponding hydraulic solenoid valve duty cycles, with a one-to-one correspondence between the engine compression ratio and the hydraulic solenoid valve duty cycle.

[0111] After obtaining the third preset data, the duty cycle of the hydraulic solenoid valve corresponding to the desired compression ratio of the current engine is found in the third preset data and used as the target duty cycle of the hydraulic solenoid valve.

[0112] Specifically, the third preset data can be converted into a Map to obtain the third Map, which is then built into the ECU. After determining that the engine compression ratio needs to be adjusted, the target duty cycle of the hydraulic solenoid valve can be determined directly in the third Map based on the current desired compression ratio, thereby reducing the amount of data processing and improving the speed of obtaining the target duty cycle of the hydraulic solenoid valve.

[0113] S42: Controls the hydraulic solenoid valve according to the target duty cycle to perform PID control on the engine's compression ratio.

[0114] After determining the target duty cycle of the hydraulic solenoid valve, the solenoid valve is controlled according to the target duty cycle to perform PID control on the engine's compression ratio. PID control, or Proportional, Integral, and Differential control, calculates the input deviation (the difference between the desired and actual compression ratio) according to a proportional, integral, and derivative function. The result is used to control the output, resulting in high data control accuracy.

[0115] The target duty cycle can be directly sent to the hydraulic solenoid valve, and the compression ratio of the engine can be controlled by PID control through the control of the hydraulic solenoid valve, so that the actual compression ratio of the engine can quickly approach the desired compression ratio.

[0116] In one embodiment, after determining the target duty cycle of the hydraulic solenoid valve, the current operating duty cycle of the hydraulic solenoid valve can also be obtained. Then, duty cycle control information is generated based on the operating duty cycle and the target duty cycle. The duty cycle control information consists of multiple duty cycles from the operating duty cycle to the target duty cycle. Finally, the hydraulic solenoid valve is controlled according to the duty cycle control information to perform PID control on the engine's compression ratio, so that the engine's actual compression ratio gradually approaches the desired compression ratio, reducing fluctuations in the engine's compression ratio and ensuring the stability of engine operation.

[0117] For example, if the current duty cycle of the hydraulic solenoid valve is 10% and the target duty cycle is 20%, then the duty cycle control information includes multiple duty cycles such as 12%, 14%, 16%, 18%, and 20%. After obtaining the duty cycle control information, the ECU sends the duty cycles of 12%, 14%, 16%, 18%, and 20% to the hydraulic solenoid valve in sequence, so that the actual compression ratio of the engine gradually approaches the desired compression ratio after multiple changes, thereby achieving the compression ratio adjustment requirement.

[0118] In this embodiment, the current working duty cycle of the hydraulic solenoid valve is 10%, and the target duty cycle is 20%. Therefore, the duty cycle control information includes multiple duty cycles such as 12%, 14%, 16%, 18%, and 20%. This is only an example for illustration. In other embodiments, the current working duty cycle and the target duty cycle of the hydraulic solenoid valve can be other values, and the multiple duty cycles included in the duty cycle control information can be other values, which will not be elaborated here.

[0119] S43: In the PID control process, determine whether the compression ratio difference between the desired compression ratio and the actual compression ratio meets the preset conditions.

[0120] In the process of PID control of the engine's compression ratio, it is necessary to acquire the engine's actual speed and load in real time, as well as the control shaft phase of the compression ratio control axis. This allows for the determination of the desired compression ratio based on the actual engine speed and load, and the determination of the actual compression ratio based on the control shaft phase. Furthermore, it determines whether the compression ratio difference between the desired and actual compression ratios meets a preset condition, i.e., whether the actual compression ratio has been adjusted to be close to the desired compression ratio. In this embodiment, if the compression ratio evaluation parameter value is Δε, the difference between the desired and actual compression ratios can be used to determine whether the compression ratio evaluation parameter value meets the preset condition during PID control.

[0121] This includes determining whether the compression ratio difference Δε between the desired and actual compression ratios of the current engine meets preset conditions, including:

[0122] a. When Δε is greater than 0, determine whether Δε is greater than the first fluctuation threshold Δε. llimit If Δε is less than or equal to the first fluctuation threshold Δε llimit That is, Δε < 0 and Δε ≤ Δε llimit When the engine's desired compression ratio and actual compression ratio are within a certain range, the difference between the two values ​​satisfies the preset condition, indicating that the engine's actual compression ratio has been adjusted to near the desired compression ratio. In this case, the hydraulic solenoid valve can be kept operating at its current duty cycle. If Δε is greater than the first fluctuation threshold, i.e., Δε < 0 and Δε > Δε, then... llimit If the difference between the engine's desired compression ratio and the actual compression ratio does not meet the preset condition, it means that the engine's actual compression ratio has not been adjusted to be close to the desired compression ratio. In this case, it is necessary to continue to change the duty cycle of the hydraulic solenoid valve, using the target duty cycle as the target, until Δε≤Δε llimit .

[0123] b. When Δε is less than 0, determine whether the absolute value of Δε is greater than the second fluctuation threshold Δε. ulimit If the absolute value of Δε is less than or equal to the second fluctuation threshold, i.e., Δε < 0 and |Δε| ≤ Δε ulimit When the engine's desired compression ratio and actual compression ratio are within a certain range, the difference between the two values ​​satisfies the preset condition, indicating that the engine's actual compression ratio has been adjusted to near the desired compression ratio. In this case, the hydraulic solenoid valve can be kept operating at its current duty cycle. If the absolute value of Δε is greater than the second fluctuation threshold, i.e., Δε < 0 and |Δε| > Δε, then... ulimitIf the difference between the engine's desired compression ratio and the actual compression ratio does not meet the preset condition, it means that the engine's actual compression ratio has not been adjusted to be close to the desired compression ratio. In this case, it is necessary to continue to change the duty cycle of the hydraulic solenoid valve, using the target duty cycle as the target, until |Δε|≤Δε ulimit .

[0124] Steps a and b above clarify the specific process of determining whether the compression ratio difference between the engine's desired compression ratio and the actual compression ratio meets the preset conditions. Different judgment strategies are executed according to different compression ratio difference situations, ensuring the accuracy of the judgment results and keeping the engine's compression ratio in an optimal state.

[0125] S44: If the compression ratio difference meets the preset conditions, then the actual compression ratio of the engine is determined to meet the requirements.

[0126] After determining whether the compression ratio difference between the desired compression ratio and the actual compression ratio meets the preset conditions, if the compression ratio difference meets the preset conditions, it means that the actual compression ratio of the engine is close to the desired compression ratio and the engine is in the optimal compression ratio state. Then, it is determined that the actual compression ratio of the engine meets the requirements, exits the closed-loop adjustment process of the engine, and enters the normal operation mode of the engine. The actual compression ratio of the engine needs to respond according to the normal needs of the vehicle.

[0127] In this embodiment, the target duty cycle of the hydraulic solenoid valve is determined based on the third preset data and the desired compression ratio. Then, the hydraulic solenoid valve is controlled according to the target duty cycle to perform PID control on the engine's compression ratio. During the PID control process, it is determined whether the compression ratio difference between the desired compression ratio and the actual compression ratio meets the preset conditions. If the compression ratio difference meets the preset conditions, it is determined that the engine's actual compression ratio meets the requirements. This clarifies the specific process of closed-loop adjustment of the engine's compression ratio to ensure that the engine's actual compression ratio meets the requirements. PID adjustment of the engine's compression ratio is achieved based on the duty cycle of the hydraulic solenoid valve, realizing precise and efficient control of the engine's compression ratio.

[0128] In one embodiment, such as Figure 4 As shown, during the execution of step S40, i.e., the closed-loop adjustment of the engine's compression ratio, the method further includes the following steps:

[0129] S401: Monitor the rate of change of the actual compression ratio to determine whether the rate of change is within the preset rate range.

[0130] During the closed-loop adjustment of the engine's compression ratio, it is necessary to obtain the engine's actual compression ratio in real time to monitor the rate of change of the actual compression ratio and determine whether the rate of change is within the preset range.

[0131] The preset rate range is the allowable range of engine compression ratio change rates under the current engine operating conditions; the maximum value of the preset rate range is the maximum allowable compression ratio change rate threshold Δεr under the current engine operating conditions. max The minimum value of the preset rate range is the minimum allowable rate of change of compression ratio Δεr under the current engine operating conditions. min The preset speed range varies under different engine operating conditions, meaning that different speeds and loads result in different preset speed ranges. In other words, the preset speed range is determined based on the engine's real-time speed and actual load.

[0132] If the actual rate of change of compression ratio is greater than or equal to the minimum rate of change of compression ratio threshold Δεr min And the actual rate of change of the compression ratio is less than or equal to the threshold Δεr of the maximum rate of change of the compression ratio. max This indicates that the actual rate of change of the compression ratio is within a safe range, and there is no need to limit the engine speed and torque. If the actual rate of change of the compression ratio is less than the minimum compression ratio change rate threshold Δεr... min The actual rate of change of compression ratio is greater than the maximum rate of change of compression ratio threshold Δεr. max If the rate of change of the actual compression ratio is determined to be outside the safe range, it indicates that the rate of change of the actual compression ratio is too fast, which may lead to safety risks such as knocking. In order to ensure engine safety and driving safety, it is necessary to limit the engine speed and torque to shut down the engine. At the same time, it is also necessary to control the engine to issue an alarm so that the user can be informed of the change in the actual compression ratio in a timely manner and take appropriate action.

[0133] S402: If the rate of change is within the preset rate range, control the engine to operate normally.

[0134] After monitoring the rate of change of the actual compression ratio to determine whether the rate of change is within the preset rate range, if the rate of change is within the preset rate range, it means that the rate of change of the actual compression ratio is within the safe range, and there is no need to limit the engine speed and torque. Then, the engine is controlled to operate normally, and the operation of closed-loop adjustment of the engine compression ratio continues until the closed-loop adjustment process is completed.

[0135] S403: If the actual compression ratio is not within the preset speed range, the engine speed and torque will be limited until the engine stops running.

[0136] After monitoring the rate of change of the actual compression ratio to determine whether the rate of change is within the preset rate range, if the actual compression ratio is not within the preset rate range, it indicates that the rate of change of the actual compression ratio is too fast, which may lead to safety risks such as knocking. In order to ensure engine safety and driving safety, it is necessary to limit the engine speed and torque until the engine stops running to ensure driving safety.

[0137] In this embodiment, to reduce the amount of data processing during monitoring, it is necessary to monitor the rate of change of the actual compression ratio every interval t (e.g., one engine cycle). The formula for calculating the rate of change of the actual compression ratio is:

[0138] Δεr n+1 =ε n+1 -ε n ;

[0139] Where, Δεr n+1 The actual compression ratio determined for the (n+1)th cycle (e.g., the (n+1)th engine cycle), i.e., the actual compression ratio of the current engine; ε n The actual compression ratio determined for the nth cycle (e.g., n engine cycles), which is the actual compression ratio of the engine in the previous cycle.

[0140] Taking an engine cycle with an interval period t as an example, in the current engine cycle, if the actual compression ratio changes at a rate Δεr... n+1 Greater than or equal to Δεr min , and Δεr n+1 Less than or equal to Δεr max This indicates that the rate of change of the actual compression ratio in the current engine cycle is within a safe range, and there is no need to limit the engine speed and torque, thus controlling the engine to operate normally. If the rate of change of the actual compression ratio is Δεr... n+1 Less than Δεr min Or Δεr n+1 Equal to Δεr max If the actual compression ratio is not within the preset rate range, it means that the rate of change of the actual compression ratio is too fast, which may lead to safety risks such as knocking. In order to ensure engine safety and driving safety, it is necessary to limit the engine speed and torque until the engine stops running.

[0141] In each engine cycle, the rate of change of the actual compression ratio needs to be monitored to determine whether the rate of change is within the preset range. Based on the determination result, different engine control strategies are executed to ensure driving safety.

[0142] In this embodiment, during the closed-loop adjustment of the engine's compression ratio, the rate of change of the actual compression ratio is monitored to determine whether the rate of change is within a preset range. If the rate of change is within the preset range, the engine is controlled to operate normally; if the actual compression ratio is not within the preset range, the engine speed and torque are limited until the engine stops operating. The rate of change of the actual compression ratio is monitored to determine whether the rate of change is within the preset range, and then different engine control strategies are executed based on the determination results to ensure driving safety.

[0143] In one embodiment, before step S10, i.e. before determining the actual compression ratio of the engine, the method further includes the following steps:

[0144] S01: Determine if there is a malfunction in the compression ratio hydraulic system.

[0145] After the vehicle is powered on, the ECU needs to determine whether there is a fault in the compression ratio hydraulic system in order to execute engine protection strategies based on the fault condition.

[0146] The process of determining whether the compression ratio hydraulic system is malfunctioning includes: after the vehicle is powered on, checking whether the phase sensor on the compression ratio control shaft of the compression ratio hydraulic system is malfunctioning, and checking whether the hydraulic solenoid valve in the compression ratio hydraulic system is malfunctioning. If either the phase sensor on the compression ratio control shaft or the hydraulic solenoid valve malfunctions, the compression ratio hydraulic system is determined to be malfunctioning; if neither the phase sensor nor the hydraulic solenoid valve malfunctions, the compression ratio hydraulic system is determined to be functioning correctly. When the phase sensor on the compression ratio control shaft malfunctions, the accurate actual compression ratio of the engine cannot be obtained; when the hydraulic solenoid valve malfunctions, the engine compression ratio cannot be controlled via the hydraulic solenoid valve. Therefore, when either the phase sensor or the hydraulic solenoid valve on the compression ratio control shaft malfunctions, the actual engine condition cannot be determined. To ensure engine safety and driving safety, it is necessary to control the engine compression ratio control system into a fault mode and activate the engine alarm so that the user is promptly informed of the malfunction in the compression ratio hydraulic system.

[0147] The process for determining whether the phase sensor on the compression ratio control shaft in the compression ratio hydraulic system is as follows: Each time the ECU powers on, it acquires the control shaft phase of the compression ratio control shaft and determines whether the acquired phase is normal. If the control shaft phase is less than a preset phase value, greater than a preset phase value, exhibits abnormal phase values ​​(e.g., no phase value), or other abnormalities, then the phase sensor is determined to have a signal malfunction. When the phase sensor malfunctions, it is determined that the phase sensor is faulty, and the engine cannot determine the current control shaft phase status through the sensor, i.e., it cannot determine the current compression ratio state, posing a safety risk. The engine issues an alarm, and the engine compression ratio control system enters a fault mode.

[0148] The process for determining whether the hydraulic solenoid valve in the compression ratio hydraulic system is faulty is as follows: Each time the ECU is powered on, it performs a self-check on the hydraulic solenoid valve and determines whether the hydraulic solenoid valve is normal. If the solenoid valve has any fault such as hardware damage, inability to be powered, or unreasonable signal, the hydraulic solenoid valve is faulty. The hydraulic solenoid valve cannot accept the execution command fed back by the ECU to perform phase holding and switching actions on the compression ratio control shaft. That is, the engine compression ratio cannot be maintained and switched, which poses a safety risk. The engine alarms, and the engine compression ratio control system enters fault mode.

[0149] In this embodiment, fault detection is performed on the hydraulic solenoid valve and the phase sensor on the compression ratio control shaft. Based on the fault detection results of the hydraulic solenoid valve and the phase sensor, it is determined whether the compression ratio hydraulic system has a fault. This clarifies the specific process for determining whether the compression ratio hydraulic system has a fault, providing an accurate basis for subsequent engine control.

[0150] S02: If the compression ratio hydraulic system is not faulty, obtain the actual compression ratio of the engine.

[0151] After determining whether the compression ratio hydraulic system is faulty, if the compression ratio hydraulic system is not faulty, it means that the compression ratio of the engine can be adjusted normally through the compression ratio hydraulic system. Then, the actual compression ratio of the engine is obtained, and the compression ratio evaluation parameter value is determined based on the actual compression ratio and the desired compression ratio. Then, the compression ratio of the engine is adjusted based on the compression ratio evaluation parameter value.

[0152] S03: If the compression ratio hydraulic system malfunctions, determine whether the compression ratio hydraulic system has a physical locking function.

[0153] After determining whether the compression ratio hydraulic system has malfunctioned, if the compression ratio hydraulic system has malfunctioned, it means that the compression ratio of the engine cannot be adjusted through the compression ratio hydraulic system, and the engine has a safety risk. In this case, a fault prompt is sent to the user, and it is determined whether the compression ratio hydraulic system has a physical lock-up function. Based on the result of the physical lock-up function judgment, different engine control strategies are executed.

[0154] Among these methods, determining whether the compression ratio hydraulic system has a physical lock-up function is achieved by acquiring the vehicle's F... lock The signal value is determined, F lock The signal value is assigned when the variable compression ratio mechanism of the compression ratio hydraulic system completes its operation. If F lock An equal value of 1 indicates that the compression ratio hydraulic system has a physical lock-up function; if F lock A value of 0 indicates that the compression ratio hydraulic system does not have a physical locking function.

[0155] S04: If the compression ratio hydraulic system has a physical lock-up function, the compression ratio of the engine will be controlled according to the fourth preset data when the user has a vehicle usage requirement.

[0156] After determining that the compression ratio hydraulic system has malfunctioned and whether it has a physical lock-up function, if the compression ratio hydraulic system has a physical lock-up function, it means that the compression ratio hydraulic system is still under control. In this case, a confirmation message is sent to the user to report the malfunction and confirm whether the user needs to continue using the vehicle. If the user's instruction to continue using the vehicle is received, it is determined that the user has a need to use the vehicle. The fourth preset data needs to be obtained, and the compression ratio of the engine is controlled according to the fourth preset data to ensure that the vehicle can run safely while meeting the user's needs and ensuring the user's safety.

[0157] Among them, the fourth preset data is the compression ratio of the engine under different operating conditions in the fault mode, and the fourth preset data is the data pre-calibrated based on the test data.

[0158] S05: If the compression ratio hydraulic system does not have a physical lock-up function, the engine speed and torque will be limited to stop the engine.

[0159] After determining that the compression ratio hydraulic system has malfunctioned and whether it has a physical lock-up function, if the compression ratio hydraulic system does not have a physical lock-up function, the engine is still under control. In this case, the engine speed and torque are limited by controlling parameters such as fuel injection ignition and timing phase, so that the engine can be stopped smoothly to prevent engine damage or even safety accidents.

[0160] In this embodiment, before determining the actual compression ratio of the engine, it is necessary to determine whether the compression ratio hydraulic system is faulty. If the compression ratio hydraulic system is not faulty, the actual compression ratio of the engine is obtained. If the compression ratio hydraulic system is faulty, it is determined whether the compression ratio hydraulic system has a physical lock-up function. If the compression ratio hydraulic system has a physical lock-up function, when the user has a vehicle usage need, the engine compression ratio is controlled according to the fourth preset data. This clarifies the analysis and processing process of the engine compression ratio in fault modes. When the compression ratio hydraulic system is faulty, a safe driving strategy is executed, which can ensure that the engine can run safely or stop smoothly, avoid safety accidents involving the vehicle and its occupants, and ensure driving safety.

[0161] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0162] In one embodiment, an engine compression ratio control device is provided, which corresponds one-to-one with the engine compression ratio control method described in the above embodiments. For example... Figure 5 As shown, the engine compression ratio control device includes a first determining module 501, a second determining module 502, a third determining module 503, and an adjusting module 504. Detailed descriptions of each functional module are as follows:

[0163] The first determining module 501 is used to determine the actual compression ratio of the engine and the desired compression ratio of the engine.

[0164] The second determining module 502 is used to determine the compression ratio evaluation parameter value of the engine based on the engine's expected compression ratio and actual compression ratio.

[0165] The third determining module 503 is used to determine whether the engine needs to be adjusted in terms of compression ratio based on the compression ratio evaluation parameter value.

[0166] The adjustment module 504 is used to perform closed-loop adjustment of the engine's compression ratio if the compression ratio adjustment of the engine is required, so that the actual compression ratio of the engine meets the requirements.

[0167] Furthermore, during the closed-loop adjustment of the engine's compression ratio, the adjustment module 504 is specifically used for:

[0168] Monitor the rate of change of the actual compression ratio to determine whether the rate of change is within the preset rate range;

[0169] If the rate of change is within the preset rate range, the engine will be controlled to operate normally.

[0170] If the actual compression ratio is not within the preset range, the engine speed and torque will be limited until the engine stops running.

[0171] Furthermore, after determining the actual compression ratio of the engine, the first determining module 501 is also used for:

[0172] Determine whether the actual compression ratio is within the preset compression ratio range;

[0173] If the actual compression ratio is within the preset compression ratio range, the engine will be controlled to operate normally.

[0174] If the actual compression ratio is not within the preset compression ratio range, the engine speed and torque will be limited until the engine stops running.

[0175] Furthermore, the first determining module 501 is specifically used for:

[0176] Determine the actual engine speed and actual load, and determine the control shaft phase of the compression ratio control shaft;

[0177] The actual compression ratio of the engine is determined based on the first preset data and the control shaft phase. The first preset data is the compression ratio of the engine at different control shaft phase values ​​during actual operation.

[0178] Based on the second preset data, the actual speed, and the actual load, the desired compression ratio of the engine is determined. The second preset data is the pre-calibrated optimal compression ratio of the engine under different operating conditions.

[0179] Furthermore, the second determining module 503 is specifically used for:

[0180] When the compression ratio evaluation parameter value is positive, it is determined whether the engine compression ratio needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the first fluctuation threshold.

[0181] When the compression ratio evaluation parameter value is negative, it is determined whether the engine compression ratio needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the second fluctuation threshold.

[0182] Furthermore, the engine's compression ratio is controlled by a compression ratio hydraulic system, which includes a hydraulic solenoid valve. The adjustment module 504 is specifically used for:

[0183] Based on the third preset data and the desired compression ratio, the target duty cycle of the hydraulic solenoid valve is determined. The third preset data includes different engine compression ratios and the corresponding hydraulic solenoid valve duty cycles.

[0184] The hydraulic solenoid valve is controlled according to the target duty cycle to perform PID control on the engine's compression ratio.

[0185] In the PID control process, it is determined whether the compression ratio difference between the desired compression ratio and the actual compression ratio meets the preset conditions.

[0186] If the compression ratio difference meets the preset conditions, then the actual compression ratio of the engine is determined to meet the requirements.

[0187] Furthermore, before determining the actual compression ratio of the engine, the first determining module 501 is specifically used for:

[0188] Determine if there is a malfunction in the compression ratio hydraulic system;

[0189] If the compression ratio hydraulic system is functioning correctly, the actual compression ratio of the engine is obtained.

[0190] If the compression ratio hydraulic system malfunctions, determine whether the compression ratio hydraulic system has a physical locking function;

[0191] If the compression ratio hydraulic system has a physical lock-up function, then when the user has a need to use the vehicle, the compression ratio of the engine is controlled according to the fourth preset data, which is the compression ratio of the engine under different operating conditions in the fault mode of the fourth preset data.

[0192] Specific limitations regarding the engine compression ratio control device can be found in the limitations of the engine compression ratio control method described above, and will not be repeated here. Each module in the aforementioned engine compression ratio control device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0193] In one embodiment, an engine compression ratio control device is provided, comprising a processor, a memory, and a database connected via a system bus. The processor provides computational and control capabilities. The memory includes a storage medium and internal memory. The storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs stored in the storage medium. The database stores first preset data, second preset data, third preset data, and fourth preset data, etc. When the computer program is executed by the processor, it implements an engine compression ratio control method.

[0194] In one embodiment, such as Figure 6As shown, an engine compression ratio control device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the engine compression ratio control method described above.

[0195] In one embodiment, a readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the engine compression ratio control method described above.

[0196] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0197] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0198] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for controlling the compression ratio of an engine, characterized in that, include: Determine the actual compression ratio of the engine, and determine the desired compression ratio of the engine; Based on the engine's expected compression ratio and actual compression ratio, a compression ratio evaluation parameter value for the engine is determined, wherein the compression ratio evaluation parameter value is the real-time difference between the engine's expected compression ratio and actual compression ratio. Based on the compression ratio evaluation parameter value, determine whether the engine needs compression ratio adjustment; If it is necessary to adjust the compression ratio of the engine, the compression ratio of the engine shall be adjusted in a closed loop so that the actual compression ratio of the engine meets the requirements; The step of determining whether the engine needs compression ratio adjustment based on the compression ratio evaluation parameter value includes: When the compression ratio evaluation parameter value is positive, it is determined whether the compression ratio of the engine needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the first fluctuation threshold. When the compression ratio evaluation parameter value is negative, it is determined whether the compression ratio of the engine needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the second fluctuation threshold. Wherein, the first fluctuation threshold is a pre-calibrated lower limit threshold for engine compression ratio fluctuation, which is obtained by calibration based on engine compression ratio test results and is the minimum allowable difference between the expected engine compression ratio and the actual compression ratio; the second fluctuation threshold is a pre-calibrated upper limit threshold for engine compression ratio fluctuation, which is obtained by calibration based on engine compression ratio test results and is the maximum allowable difference between the expected engine compression ratio and the actual compression ratio.

2. The engine compression ratio control method as described in claim 1, characterized in that, During the closed-loop adjustment of the compression ratio of the engine, the method further includes: The rate of change of the actual compression ratio is monitored to determine whether the rate of change is within a preset rate range; If the rate of change is within the preset rate range, then the engine is controlled to operate normally; If the actual compression ratio is not within the preset rate range, the engine speed and torque are limited until the engine stops operating.

3. The engine compression ratio control method as described in claim 1, characterized in that, After determining the actual compression ratio of the engine, the method further includes: Determine whether the actual compression ratio is within the preset compression ratio range; If the actual compression ratio is within the preset compression ratio range, then the engine is controlled to operate normally; If the actual compression ratio is not within the preset compression ratio range, the engine speed and torque are limited until the engine stops running.

4. The engine compression ratio control method as described in claim 1, characterized in that, Determining the actual compression ratio of the engine and determining the desired compression ratio of the engine includes: Determine the actual speed and actual load of the engine, and determine the control shaft phase of the compression ratio control shaft; The actual compression ratio of the engine is determined based on the first preset data and the control shaft phase. The first preset data is the compression ratio of the engine at different control shaft phase values ​​during actual operation. Based on the second preset data, the actual speed, and the actual load, the desired compression ratio of the engine is determined. The second preset data is a pre-calibrated optimal compression ratio of the engine under different operating conditions.

5. The engine compression ratio control method according to any one of claims 1-4, characterized in that, The compression ratio of the engine is controlled by a compression ratio hydraulic system, which includes a hydraulic solenoid valve. The closed-loop adjustment of the engine's compression ratio to ensure that the actual compression ratio of the engine meets the requirements includes: The target duty cycle of the hydraulic solenoid valve is determined based on the third preset data, the desired compression ratio, and the actual compression ratio. The third preset data includes different engine compression ratios and the corresponding hydraulic solenoid valve duty cycles. The hydraulic solenoid valve is controlled according to the target duty cycle to perform PID control on the compression ratio of the engine; During the PID control process, it is determined whether the compression ratio difference between the desired compression ratio and the actual compression ratio meets a preset condition. If the compression ratio difference meets the preset condition, then the actual compression ratio of the engine is determined to meet the requirements.

6. The engine compression ratio control method according to any one of claims 1-4, characterized in that, Before determining the actual compression ratio of the engine, the method further includes: Determine if there is a malfunction in the compression ratio hydraulic system; If the compression ratio hydraulic system is not faulty, then the actual compression ratio of the engine is obtained; If the compression ratio hydraulic system malfunctions, determine whether the compression ratio hydraulic system has a physical locking function; If the compression ratio hydraulic system has a physical locking function, then when the user has a need to use the vehicle, the compression ratio of the engine is controlled according to the fourth preset data, which is the compression ratio of the engine under different operating conditions in the fault mode.

7. An engine compression ratio control device, characterized in that, include: The first determining module determines the actual compression ratio of the engine and the desired compression ratio of the engine. The second determining module determines the compression ratio evaluation parameter value of the engine based on the expected compression ratio and the actual compression ratio of the engine. The compression ratio evaluation parameter value is the real-time difference in compression ratio between the expected compression ratio and the actual compression ratio of the engine. The third determining module uses the compression ratio evaluation parameter value to determine whether the engine needs to be adjusted in terms of compression ratio. The adjustment module is used to perform closed-loop adjustment of the engine's compression ratio if it is necessary to adjust the engine's compression ratio, so that the actual compression ratio of the engine meets the requirements. The step of determining whether the engine needs compression ratio adjustment based on the compression ratio evaluation parameter value includes: When the compression ratio evaluation parameter value is positive, it is determined whether the compression ratio of the engine needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the first fluctuation threshold. When the compression ratio evaluation parameter value is negative, it is determined whether the compression ratio of the engine needs to be adjusted based on the magnitude of the compression ratio evaluation parameter value and the second fluctuation threshold. Wherein, the first fluctuation threshold is a pre-calibrated lower limit threshold for engine compression ratio fluctuation, which is obtained by calibration based on engine compression ratio test results, and is the minimum allowable difference between the expected engine compression ratio and the actual compression ratio; the second fluctuation threshold is a pre-calibrated upper limit threshold for engine compression ratio fluctuation, which is obtained by calibration based on engine compression ratio test results, and is the maximum allowable difference between the expected engine compression ratio and the actual compression ratio.

8. An engine compression ratio control device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the engine compression ratio control method as described in any one of claims 1 to 6.

9. A readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the engine compression ratio control method as described in any one of claims 1 to 6.

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