Engine piston cooling and lubrication control method and system based on digital temperature measurement
By optimizing oil nozzle control through digital temperature measurement and simulation technology, the problem of insufficient engine piston cooling was solved, resulting in reduced oil pump power consumption and improved engine reliability, especially with a significant reduction in fuel consumption in low-to-medium load areas.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SINO TRUK JINAN POWER CO LTD
- Filing Date
- 2023-09-27
- Publication Date
- 2026-05-26
AI Technical Summary
Existing technologies lack sufficient means to detect piston cooling requirements in engines, leading to increased oil pump power consumption or insufficient piston cooling, which can cause problems such as engine cylinder scoring.
The piston temperature is monitored in real time using digital temperature measurement methods. Combined with finite element simulation and performance tests, the minimum oil pressure under the open and closed states of the oil nozzle is determined. The oil flow is optimized by controlling the variable flow oil pump and solenoid valve to meet the piston cooling and lubrication requirements.
It achieves the goal of reducing oil pump power consumption while ensuring engine reliability and safety, and reducing fuel consumption, especially with significant fuel savings in low-to-medium load areas, while fuel consumption reduction is less pronounced in high-load areas.
Smart Images
Figure CN117108390B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of automotive design technology, and in particular to an engine piston cooling and lubrication control method and system based on digital temperature measurement. Background Technology
[0002] To improve engine thermal efficiency and reduce accessory power consumption, an increasing number of engines are adopting variable flow oil pumps and electronically controlled oil nozzles to reduce oil flow during partial engine loads, thereby reducing oil pump power consumption. However, during the calibration of variable flow oil pumps and electronically controlled oil nozzles, OEMs often focus more on the reliability of engine friction pairs from a lubrication perspective, neglecting or lacking the means to detect the critical factor of piston cooling requirements. This often results in providing more or less oil flow for cooling, ultimately leading to increased oil pump power consumption or serious problems such as engine cylinder scoring due to insufficient piston cooling. Summary of the Invention
[0003] This application provides a method and system for controlling engine piston cooling and lubrication based on digital temperature measurement to solve the above-mentioned problems.
[0004] This application provides a method and system for controlling engine piston cooling and lubrication based on digital temperature measurement. It is used to calibrate the oil nozzles controlled by the variable flow oil pump and solenoid valve, determining the operating range when the oil nozzles are closed (no oil cooling the piston) and the minimum main oil passage pressure required to meet piston cooling needs when the oil nozzles are open (oil cooling the piston). Combined with the minimum main oil passage pressure required for lubrication, the oil pressure calibration MAP is determined, reducing the power consumption of the variable flow oil pump while ensuring engine reliability.
[0005] This application provides an embodiment of an engine piston cooling and lubrication control method based on digital temperature measurement, the method comprising:
[0006] Step S1: Real-time monitoring of piston operating temperature using digital temperature measurement method;
[0007] Step S2: Determine the operating range where the oil nozzles are closed;
[0008] Step S3: Determine the minimum main oil passage oil pressure that meets the piston cooling and lubrication requirements when the oil nozzle is open.
[0009] In one implementation of this application, step S3 specifically includes:
[0010] Step S31: Based on the simulation calculation results of the flow and pressure characteristics of each friction pair and lubrication element and the actual engine bench test data, determine the initial oil pressure and target oil pressure of the main oil passage under the external characteristics of the diesel engine, calibrate the variable flow oil pump, and set the duty cycle of the solenoid valve.
[0011] Step S32: Based on the results of finite element simulation and performance tests of the piston's working state, determine the maximum allowable long-term normal operating temperature for each key component of the piston.
[0012] Step S33: Perform an engine external characteristic test under the initial oil pressure and with the oil nozzle normally open.
[0013] In one implementation of this application, step S33 specifically includes:
[0014] The temperature distribution of the piston at various rotational speeds is obtained by digital temperature measurement and compared with the maximum allowable temperature of the piston.
[0015] If the piston temperature is higher than the maximum allowable temperature at the operating point, the oil pressure in the main oil passage is increased by the variable flow oil pump to reduce the tested piston temperature to the maximum allowable piston temperature; if the piston temperature is lower than the maximum allowable temperature at the operating point, the oil pressure in the main oil passage is decreased by the variable flow oil pump to increase the tested piston temperature to the maximum allowable piston temperature.
[0016] The oil pressure is determined to be the minimum oil pressure that meets the piston cooling requirements under the given external characteristics.
[0017] The oil pressure is compared with the target oil pressure at the same speed, and the larger value is taken to obtain the minimum oil pressure that meets the requirements of lubrication and piston cooling.
[0018] In one implementation of this application, the method further includes:
[0019] Plot the rotational speed on the horizontal axis and the oil pressure on the vertical axis to obtain the rotational speed versus minimum oil pressure curve that satisfies lubrication and piston cooling under the external characteristics.
[0020] In one implementation of this application, the method further includes:
[0021] Determine the piston universal temperature map (MAP) for the oil nozzle under normal opening and closing conditions;
[0022] Based on the universal characteristic piston temperature measurement results and boundary pressures, as well as the lubrication system boundary pressures, the MAP diagram of the closed oil nozzle and the final main oil passage pressure are calibrated.
[0023] In one implementation of this application, the step of determining the piston universal temperature MAP diagrams of the oil nozzle in its normal open and closed states specifically involves:
[0024] The piston cooling oil nozzles are open normally, and the universal characteristic working condition sweep is carried out. During the test, the piston temperature at each working condition point is detected and recorded in real time.
[0025] With the piston cooling oil nozzle closed, perform a universal characteristic test and record parameters such as piston temperature, specific oil consumption, and oil pressure at each test point. Monitor the piston temperature in real time during the test to prevent the piston from exceeding its limit temperature and causing cylinder scoring.
[0026] In one implementation of this application, the step of calibrating the MAP diagram of the oil nozzle closure and the final main oil passage pressure based on the universal characteristic piston temperature measurement results and boundary pressures, as well as the lubrication system boundary pressures, specifically involves:
[0027] Under defined operating conditions, within the engine operating range where the piston temperature does not exceed the maximum allowable temperature, the solenoid valve controls the piston cooling oil nozzle to close, and the variable flow oil pump lowers the main oil passage pressure to reduce the oil flow.
[0028] In the piston overheating operating range, the solenoid valve controls the piston cooling oil nozzle to open normally, and adjusts the variable displacement oil pump to change the main oil passage oil pressure from high to low until the piston temperature approaches the maximum allowable temperature limit. At this time, the main oil passage oil pressure is the minimum pressure to meet the piston cooling requirements.
[0029] Repeat the above steps until all operating points have been calibrated.
[0030] This application also provides an engine piston cooling and lubrication control system based on digital temperature measurement, which applies the aforementioned engine piston cooling and lubrication control method based on digital temperature measurement. The system includes: a variable flow oil pump, an active control solenoid valve, an auxiliary oil passage oil nozzle, a temperature measuring piston, and a temperature detection system.
[0031] This application provides an engine piston cooling and lubrication control method and system based on digital temperature measurement. By using digital temperature measurement, the piston operating temperature is dynamically detected in real time, providing real-time and accurate calibration data for the lubrication system of the diesel engine, including the variable flow oil pump and the electronically controlled oil nozzle. This improves the monitoring factors for the calibration of the diesel engine lubrication system, forms a new closed-loop control, and minimizes the power consumption of the variable flow oil pump under the premise of safe engine operation. Attached Figure Description
[0032] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0033] Figure 1 A flowchart of an engine piston cooling and lubrication control method based on digital temperature measurement is provided for an embodiment of this application;
[0034] Figure 2 This is a schematic diagram of the calibration logic in an embodiment of this application;
[0035] Figure 3 This is a diagram showing the main oil passage oil pressure of the engine's external characteristics according to an embodiment of this application.
[0036] Figure 4 This is a universal MAP diagram of piston temperature measurement with the oil nozzle closed, as shown in the embodiment of this application.
[0037] Figure 5 This is a universal MAP diagram showing the fuel consumption difference in an embodiment of this application.
[0038] Figure 6 This is a diagram illustrating the composition of an engine piston cooling and lubrication control system based on digital temperature measurement, as provided in an embodiment of this application. Detailed Implementation
[0039] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0040] This application provides a method and system for controlling engine piston cooling and lubrication based on digital temperature measurement. The technical solution proposed in this application will be described in detail below with reference to the accompanying drawings.
[0041] Figure 1 This is a flowchart illustrating an engine piston cooling and lubrication control method based on digital temperature measurement, provided as an embodiment of this application. Figure 1 As shown, the method mainly includes the following steps:
[0042] Step S1: Real-time monitoring of piston operating temperature using digital temperature measurement method;
[0043] Step S2: Determine the operating range where the oil nozzles are closed;
[0044] Step S3: Determine the minimum main oil passage oil pressure that meets the piston cooling and lubrication requirements when the oil nozzle is open.
[0045] In this embodiment of the application, step S3 specifically includes:
[0046] Step S31: Based on the simulation results of the flow and pressure characteristics of each friction pair and lubrication element, and the actual engine bench test data, determine the initial oil pressure and target oil pressure of the main oil passage under the external characteristics of the diesel engine, calibrate the variable flow oil pump, and set the duty cycle of the solenoid valve; the calibration logic diagram is shown below. Figure 2 As shown.
[0047] Step S32: Based on the results of finite element simulation and performance tests of the piston's working state, determine the maximum allowable long-term normal operating temperature for each key component of the piston.
[0048] Step S33: Perform an engine external characteristic test under the initial oil pressure and with the oil nozzle normally open.
[0049] In this embodiment of the application, step S33 specifically includes:
[0050] The temperature distribution of the piston at various rotational speeds is obtained by digital temperature measurement and compared with the maximum allowable temperature of the piston.
[0051] If the piston temperature exceeds the maximum permissible operating temperature, the main oil passage oil pressure is increased via a variable flow oil pump to lower the tested piston temperature to the maximum permissible piston temperature. Conversely, if the piston temperature falls below the maximum permissible operating temperature, the main oil passage oil pressure is decreased via a variable flow oil pump to raise the tested piston temperature to the maximum permissible piston temperature. The engine external characteristic main oil passage oil pressure diagram is shown below. Figure 3 As shown.
[0052] The oil pressure is determined to be the minimum oil pressure that meets the piston cooling requirements under the given external characteristics.
[0053] The oil pressure is compared with the target oil pressure at the same speed, and the larger value is taken to obtain the minimum oil pressure that meets the requirements of lubrication and piston cooling.
[0054] In this embodiment of the application, the method further includes:
[0055] Plot the rotational speed on the horizontal axis and the oil pressure on the vertical axis to obtain the rotational speed versus minimum oil pressure curve that satisfies lubrication and piston cooling under the external characteristics.
[0056] In this embodiment of the application, the method further includes:
[0057] Determine the piston universal temperature map (MAP) for the oil nozzle under normal opening and closing conditions;
[0058] Based on the universal characteristic piston temperature measurement results and boundary pressures, as well as the lubrication system boundary pressures, the MAP diagram of the closed oil nozzle and the final main oil passage pressure are calibrated.
[0059] In this embodiment of the application, the step of determining the piston universal temperature MAP diagrams of the oil nozzle in the normal open and closed states specifically involves:
[0060] The piston cooling oil nozzles are open normally, and the universal characteristic working condition sweep is carried out. During the test, the piston temperature at each working condition point is detected and recorded in real time.
[0061] With the piston cooling oil nozzle closed, perform a universal characteristic test and record parameters such as piston temperature, specific oil consumption, and oil pressure at each test point. Monitor the piston temperature in real time during the test to prevent the piston from exceeding its limit temperature and causing cylinder scoring.
[0062] In this embodiment of the application, the step of calibrating the MAP diagram of the oil nozzle closure and the final main oil passage pressure based on the universal characteristic piston temperature measurement results and boundary pressures, as well as the lubrication system boundary pressures, specifically involves:
[0063] Under defined operating conditions, within the engine operating range where the piston temperature does not exceed the maximum allowable temperature, the solenoid valve controls the piston cooling oil nozzle to close, and the variable flow oil pump lowers the main oil passage pressure to reduce the oil flow.
[0064] In the piston overheating operating range, the solenoid valve controls the piston cooling oil nozzle to open normally, and adjusts the variable displacement oil pump to change the main oil passage oil pressure from high to low until the piston temperature approaches the maximum allowable temperature limit. At this time, the main oil passage oil pressure is the minimum pressure to meet the piston cooling requirements.
[0065] Repeat the above steps until all operating points are calibrated. The universal MAP graph for piston temperature measurement with the oil nozzle closed is shown below. Figure 4 As shown.
[0066] like Figure 5 The figure shows the difference in specific fuel consumption between two calibration programs performed on the same engine test bench: one using a variable flow oil pump and solenoid valve-controlled nozzle based on piston digital temperature measurement, and the other without. Compared to the calibration program without piston temperature measurement, the program using a variable flow oil pump and solenoid valve-controlled nozzle based on piston digital temperature measurement effectively reduces engine fuel consumption, especially in low-load areas. Due to precise calibration of the oil nozzle's closed operating condition, the engine's demand for oil pressure and flow is lower, resulting in a fuel consumption benefit of up to 10 g / kW·h. In high-load areas, to ensure engine lubrication, the specific fuel consumption reduction is less significant, approximately 1–3 g / kW·h.
[0067] This application also provides an engine piston cooling and lubrication control system based on digital temperature measurement, which applies the aforementioned engine piston cooling and lubrication control method based on digital temperature measurement. The system includes: a variable flow oil pump, an active control solenoid valve, an auxiliary oil passage oil nozzle, a temperature measuring piston, and a temperature detection system.
[0068] The above describes an engine piston cooling and lubrication control method based on digital temperature measurement, as provided in this application. Based on the same inventive concept, this application also provides an engine piston cooling and lubrication control system based on digital temperature measurement. Figure 6A schematic diagram of an engine piston cooling and lubrication control system based on digital temperature measurement is provided for an embodiment of this application, as shown below. Figure 6 As shown, the system mainly includes: a variable flow oil pump, an active control solenoid valve, an auxiliary oil passage oil nozzle, a temperature measuring piston, and a temperature detection system.
[0069] The various embodiments in this application are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.
[0070] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0071] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.
Claims
1. A method for controlling engine piston cooling and lubrication based on digital temperature measurement, characterized in that, The method includes: Step S1: Real-time monitoring of piston operating temperature using digital temperature measurement method; Step S2: Determine the operating range where the oil nozzles are closed; Step S3: Determine the minimum main oil passage oil pressure required to meet piston cooling and lubrication needs with the oil nozzle open. Specifically, Step S3 includes: Step S31: Based on simulation results of the flow and pressure characteristics of each friction pair and lubrication element, and actual engine bench test data, determine the initial and target main oil passage oil pressure under the diesel engine's external characteristics, calibrate the variable flow oil pump, and set the solenoid valve duty cycle; Step S32: Based on the results of finite element simulation and performance tests of the piston's working state, determine the maximum allowable long-term normal operating temperature for each key part of the piston; Step S33: Conduct engine external characteristic tests under the initial oil pressure and with the oil nozzle normally open.
3. Specifically: The temperature distribution of the piston at various speeds is obtained through digital temperature measurement and compared with the maximum allowable temperature of the piston. For operating points where the piston temperature is higher than the maximum allowable temperature, the main oil passage oil pressure is increased by a variable flow oil pump to lower the tested piston temperature to the maximum allowable piston temperature. For operating points where the piston temperature is lower than the maximum allowable temperature, the main oil passage oil pressure is decreased by a variable flow oil pump to raise the tested piston temperature to the maximum allowable piston temperature. The minimum oil pressure is determined to be the minimum oil pressure that meets the piston cooling requirements under the external characteristics. This pressure is compared with the target oil pressure at the same speed, and the larger value is taken to obtain the minimum oil pressure that meets the lubrication and piston cooling requirements.
2. The engine piston cooling and lubrication control method based on digital temperature measurement according to claim 1, characterized in that, The method further includes: Plot the speed on the horizontal axis and the oil pressure on the vertical axis to obtain the speed-to-minimum oil pressure curve that satisfies lubrication and piston cooling under the external characteristics.
3. The engine piston cooling and lubrication control method based on digital temperature measurement according to claim 1, characterized in that, The method further includes: Determine the piston universal temperature map (MAP) for the oil nozzle under normal opening and closing conditions; Based on the universal characteristic piston temperature measurement results and boundary pressures, as well as the lubrication system boundary pressures, the MAP diagram of the closed oil nozzle and the final main oil passage pressure are calibrated.
4. The engine piston cooling and lubrication control method based on digital temperature measurement according to claim 3, characterized in that, The specific steps for determining the piston universal temperature map (MAP) of the oil nozzle under normal opening and closing states are as follows: The piston cooling oil nozzles were opened normally, and the universal characteristic working condition was scanned. During the test, the piston temperature at each working condition point was detected and recorded in real time. With the piston cooling oil nozzle closed, perform a universal characteristic test and record the piston temperature, specific oil consumption, and oil pressure parameters at each test point. Monitor the piston temperature in real time during the test to prevent the piston from exceeding its limit temperature and causing cylinder scoring.
5. The engine piston cooling and lubrication control method based on digital temperature measurement according to claim 4, characterized in that, The process of calibrating the MAP diagram of oil nozzle closure and the final main oil passage pressure based on the universal characteristic piston temperature measurement results and boundary pressures, as well as the lubrication system boundary pressures, is as follows: Under defined operating conditions, within the engine operating range where the piston temperature does not exceed the maximum allowable temperature, the solenoid valve controls the piston cooling oil nozzle to close, and the variable flow oil pump lowers the main oil passage pressure to reduce the oil flow. In the piston overheating operating range, the solenoid valve controls the piston cooling oil nozzle to open normally, and adjusts the variable displacement oil pump to change the main oil passage oil pressure from high to low until the piston temperature approaches the maximum allowable temperature limit. At this time, the main oil passage oil pressure is the minimum pressure to meet the piston cooling requirements. Repeat the above steps until all operating points have been calibrated.
6. An engine piston cooling and lubrication control system based on digital temperature measurement, employing the engine piston cooling and lubrication control method based on digital temperature measurement as described in any one of claims 1-5, characterized in that, The system includes: a variable flow oil pump, an active control solenoid valve, an auxiliary oil passage oil nozzle, a temperature measuring piston, and a temperature detection system.