A cooling system oil temperature control method and apparatus

Abstract

The application discloses a cooling system oil temperature control method, and steps are as follows: cooling system oil temperature regulation starting condition: judging whether to enter the cooling system oil temperature regulation mode from four basic conditions; calibration target oil temperature adjustment parameter: determining the adjustment coefficient of the target oil temperature and the maximum change rate absolute value of the adjustment coefficient of the target oil temperature according to whether the piston cooling nozzle is opened; cooling system oil temperature regulation mode: when the cooling system oil temperature regulation mode is satisfied and high-intensity knock or early combustion does not occur within a certain time after the cooling system oil temperature regulation mode is exited; then the change time of the oil temperature regulation starting condition is reduced; and if the number of times of high-intensity knock or early combustion exceeds a preset number within a certain time after the cooling system oil temperature regulation mode is exited, the change time of the oil temperature regulation starting condition is increased. The application further discloses a cooling system oil temperature control device. The application adjusts the target oil temperature under different working conditions, realizes good target oil temperature control, and can be widely applied to the field of engine control.

Description

Technical Field

[0001] This invention relates to the field of engine control, and in particular to a method and apparatus for controlling the oil temperature of a cooling system. Background Technology

[0002] The engine lubrication system provides lubrication and protection to the oilers used in various engine systems. An oil pump installed on the engine can regulate oil temperature and pressure.

[0003] To improve engine lubrication and reduce the risk of overheating, it is necessary to control the engine oil at a suitable temperature.

[0004] Many businesses have also made numerous attempts in this regard:

[0005] For example, an invention with publication number CN103758629A, entitled "Engine Coolant Temperature High Temperature Protection Method," reduces output power by controlling the current of a torque solenoid valve, thereby lowering the coolant temperature. However, this solution does not consider the control of engine oil temperature based on engine protection.

[0006] Another invention, CN115167565A, entitled "A Temperature Control Device, Method, and Apparatus," includes a detection module, a control module, and an adjustment module. The detection module detects the outlet temperature of the cooling water pump; the control module compares the outlet temperature with a preset temperature threshold and outputs a control signal to the adjustment module based on the comparison result; and the adjustment module, located at the outlet of the cooling water pump, adjusts the outlet temperature based on the received control signal. By using an adjustment module at the outlet to assist in regulating the outlet temperature, the cooling water pump's outlet temperature can be more accurately controlled, enhancing the cooling system's performance and thus improving engine efficiency and safety. However, this solution also fails to consider oil temperature control for engine protection.

[0007] Based on this, the present invention proposes a method and device for controlling the oil temperature of a cooling system. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and device for controlling the oil temperature of a cooling system, which adjusts the target oil temperature under different operating conditions to achieve better target oil temperature control.

[0009] This invention provides a method for controlling engine oil temperature in a cooling system, comprising the following steps: Cooling system oil temperature regulation start-up conditions: determining whether to enter the cooling system oil temperature regulation mode based on whether four conditions are met: engine running time, high-intensity knocking or pre-ignition in the engine, deviation between the target phase and the actual phase in VVT control, and ignition angle efficiency; Calibrating target oil temperature adjustment parameters: when entering the cooling system oil temperature regulation mode, determining the target oil temperature adjustment coefficient and the absolute value of the maximum change rate of the target oil temperature adjustment coefficient based on whether the piston cooling nozzles are open; Cooling system oil temperature regulation mode: if no high-intensity knocking or pre-ignition occurs within a certain period after the cooling system oil temperature regulation mode is met and after exiting the mode, the cooling system oil temperature regulation start-up condition change time is reduced to ensure the oil temperature rises quickly; if the number of high-intensity knocking or pre-ignition occurs more than a preset number within a certain period after exiting the cooling system oil temperature regulation mode, the cooling system oil temperature regulation start-up condition change time is increased to protect the engine.

[0010] In the above technical solution, the specific process of the cooling system oil temperature regulation start-up condition step is as follows: Basic conditions: including four conditions: engine running time, engine high-intensity knocking or pre-ignition, VVT control target phase deviation from actual phase, and ignition angle efficiency; Condition met: the basic conditions are met simultaneously; or, condition not fully met: the time from the condition being fully met to the condition not being fully met does not exceed the second preset time T1, and the engine requesting ignition torque exceeds the product of the engine maximum torque and the preset coefficient r1 for the first time after the above conditions are not met simultaneously; Start-up judgment: when one of the conditions is met or the condition is not fully met, the cooling system oil temperature regulation mode is entered.

[0011] In the above technical solution, the specific contents of the basic condition steps include: engine running time: the engine running time exceeds the first preset time T0; high intensity knock or pre-ignition: when high intensity knock or pre-ignition occurs in the engine; VVT control target phase: the deviation between the VVT ​​control target phase and the actual phase is within a preset range; ignition angle efficiency: the ignition angle efficiency is not lower than a preset value.

[0012] In the above technical solution, the specific process of calibrating the target oil temperature adjustment parameters is as follows: Target oil temperature adjustment coefficient: The target oil temperature adjustment coefficient is determined by the engine speed and engine load. When the piston cooling nozzle is open, the target oil temperature adjustment coefficient is the first adjustment coefficient k1; when the piston cooling nozzle is not open, the target oil temperature adjustment coefficient is the second adjustment coefficient k2; Maximum absolute value of the maximum rate of change of the target oil temperature adjustment coefficient: When the working state of the piston cooling nozzle is switched, the maximum absolute value of the maximum rate of change of the target oil temperature adjustment coefficient is determined by the engine speed and engine coolant temperature.

[0013] In the above technical solution, the calibration basis for the first adjustment coefficient k1, the second adjustment coefficient k2 and the absolute value of the maximum change rate of the target oil temperature adjustment coefficient when the piston cooling nozzle working state is switched is that after entering the cooling system oil temperature control mode, regardless of whether the piston cooling nozzle is open or not, the engine torque accuracy is controlled within ±5Nm, and the engine does not experience high-intensity knocking or pre-ignition.

[0014] In the above technical solution, the specific process of the cooling system oil temperature control mode step is as follows: Reduce the second preset time T1: When the number of times the cooling system oil temperature control mode is satisfied exceeds the preset number, and no high-intensity knocking or pre-ignition occurs within the third preset time T2 after the cooling system oil temperature control mode is satisfied and exited, then reduce the second preset time T1; Increase the second preset time T1: When the number of times the cooling system oil temperature control mode is satisfied exceeds the preset number, and the number of times high-intensity knocking or pre-ignition occurs within the third preset time T2 after the cooling system oil temperature control mode is exited exceeds the preset number, then increase the second preset time T1.

[0015] In the above technical solution, in the step of reducing the second preset time T1, after the second preset time T1 is updated to a preset number of times, the first adjustment coefficient k1 and the second adjustment coefficient k2 are updated to 1.0 to 1.1 times the value before the update, but the final value after the update does not exceed 1.

[0016] In the above technical solution, in the step of adding the second preset time T1, after the second preset time T1 is updated to a preset number of times, the first adjustment coefficient k1 and the second adjustment coefficient k2 are updated to 0.8 to 1.0 times the value before the update, but the final value after the update is not less than 0.5.

[0017] The above technical solution also includes a step to exit the cooling system oil temperature control mode. The specific process is as follows: when exiting the cooling system oil temperature control mode, a transitional method is used to gradually restore the target oil temperature to the normal oil temperature.

[0018] The present invention also provides a cooling system oil temperature control device, which has a computer program that can execute a cooling system oil temperature control method.

[0019] The cooling system oil temperature control method and device of the present invention have the following beneficial effects:

[0020] When the engine experiences high-intensity knocking or pre-ignition, the target oil temperature is adjusted according to different operating conditions. The design is optimized by balancing engine protection, engine lubrication, and engine torque accuracy, achieving better target oil temperature control. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the overall process of the cooling system oil temperature control method of the present invention;

[0022] Figure 2 This is a flowchart illustrating the steps for setting up the cooling system oil temperature control method according to the present invention.

[0023] Figure 3 This is a flowchart illustrating the steps for calibrating the target oil temperature adjustment parameters in the cooling system oil temperature control method of the present invention.

[0024] Figure 4 This is a flowchart illustrating the steps of the cooling system oil temperature regulation mode in the cooling system oil temperature control method of the present invention.

[0025] Figure 5 This is a schematic diagram of the structure of the oil temperature control device for the cooling system of the present invention. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, but these embodiments should not be construed as limiting the present invention.

[0027] Under normal operating conditions, the target oil temperature is determined based on engine speed and engine load (engine load can be characterized by actual fresh air intake density, which refers to the actual fresh air intake density entering the cylinder). This target oil temperature is obtained through optimal calibration on an engine test bench, based on a trade-off between fuel economy and emissions. Based on this, the calibration data for this example is shown in Table 1 below:

[0028] Table 1

[0029]

[0030] See Figure 1 The present invention provides a method for controlling the oil temperature of a cooling system, comprising the following steps:

[0031] I. Cooling system oil temperature control start-up conditions, see [link / reference] Figure 2 :

[0032] 1. Basic Conditions: When the following basic conditions are met simultaneously, the engine oil temperature can be optimized, thereby protecting the engine more quickly. These basic conditions are as follows:

[0033] 1) The engine running time (the running time will be reset to zero after the engine stops until the engine is restarted) exceeds the first preset time T0, which is 30 minutes in this example;

[0034] 2) When the engine experiences high-intensity knocking (the definition of high-intensity knocking in this example is when the ignition angle is delayed by more than 8° after knocking) or when pre-ignition occurs;

[0035] 3) The deviation between the target phase and the actual phase in VVT (Variable Valve Timing) control is within the preset range (±1° crankshaft angle in this example), indicating that the oil temperature has little impact on the VVT ​​control responsiveness;

[0036] 4) The ignition angle efficiency should not be lower than the preset value (0.2 in this example). If the ignition efficiency is too low, it will affect the combustion stability of the engine, which will result in poor engine torque accuracy and abnormal combustion of the engine.

[0037] 2. Conditions met: All of the above basic conditions must be met simultaneously;

[0038] or,

[0039] 3. Condition where not all conditions are met: The time for the above basic conditions to switch from being fully met to not being fully met does not exceed the second preset time T1, and the engine's requested ignition torque exceeds the engine's maximum torque (the engine's maximum torque can be found in patent CN202010632793.4 "Method for Determining the Maximum Output Torque of a Gasoline Engine") multiplied by the preset coefficient r1 for the first time after the above basic conditions are simultaneously not met. In this embodiment, T1 is 0.5s. The preset coefficient r1 is related to the engine speed and ignition efficiency. At a certain engine speed, the higher the current ignition efficiency, the more difficult it is for the engine to increase torque through the adjustment of ignition torque (ignition efficiency). If the oil pump operation is increased at this time, it will cause an increase in electrical load, thereby affecting the torque achievement. Therefore, the higher the ignition efficiency, the smaller the preset coefficient r1, so as to quickly respond to the torque increase. The value range of the preset coefficient r1 is shown in Table 2 below:

[0040] Table 2

[0041]

[0042] In this embodiment, the calibration of T1 and r1 is based on the following: when entering the cooling system oil temperature control mode, and when exiting the mode, the accuracy of the engine torque is controlled within ±5Nm to ensure torque accuracy and drivability. Furthermore, within the third preset time T2 after exiting the cooling system oil temperature control mode (T2 is greater than T1 to ensure system stability and prevent high-intensity knocking or pre-ignition, thus protecting the engine; in this embodiment, T2 is 3 times T1, i.e., 1.5s), the engine does not experience high-intensity knocking or pre-ignition. T1 will also be learned, updated, and saved by the vehicle after power-off after calibration.

[0043] 4. Activation judgment: As long as the working condition is met or not all working conditions are met, once one of the working conditions is met, the cooling system oil temperature control mode is entered. That is, the control priority of entering the cooling system oil temperature control mode is the highest.

[0044] II. Calibration target oil temperature adjustment parameters, see [link / reference] Figure 3 :

[0045] 1. Target Oil Temperature Adjustment Coefficient: When the cooling system oil temperature control mode is activated, the target oil temperature adjustment coefficient must first be determined based on whether the piston cooling nozzles are open (piston cooling nozzles being open means they begin working to reduce the piston's thermal load and enhance lubrication of the piston pin and connecting rod bearings). Generally, when entering the cooling system oil temperature control mode, the engine oil temperature needs to be lowered to protect the engine; however, when the piston cooling nozzles are open, the engine oil temperature needs to be further lowered to reduce the piston's thermal load.

[0046] When the piston cooling nozzle is open, the first adjustment factor for the target oil temperature is k1;

[0047] When the piston cooling nozzles are not open, the second adjustment factor for the target oil temperature is k2;

[0048] The first adjustment coefficient k1 and the second adjustment coefficient k2 for the target oil temperature are jointly determined by engine speed and engine load. The calibration method is as follows: when entering the cooling system oil temperature control mode, the engine torque accuracy is controlled within ±5 Nm, and the engine does not experience high-intensity knocking or pre-ignition. The calibration data for this embodiment are shown in Tables 3 and 4 below.

[0049] Table 3

[0050]

[0051]

[0052] Table 4

[0053]

[0054] 2. Maximum absolute value of the maximum rate of change of the target oil temperature adjustment coefficient: When the piston cooling nozzle's working state changes (from open to closed, or from closed to open), the maximum absolute value of the maximum rate of change of the target oil temperature adjustment coefficient is determined by both engine speed and engine coolant temperature, as shown in Table 5 below:

[0055] Table 5

[0056]

[0057] In this embodiment, the first adjustment coefficient k1, the second adjustment coefficient k2, and the absolute value of the maximum rate of change of the adjustment coefficient of the target oil temperature when the piston cooling nozzle working state is switched are calibrated based on the fact that after entering the cooling system oil temperature control mode, regardless of whether the piston cooling nozzle is open or not, the accuracy of the engine torque is controlled within ±5Nm to ensure torque accuracy and drivability, and the engine does not experience high-intensity knocking or pre-ignition. The first adjustment coefficient k1 and the second adjustment coefficient k2 will also be learned and updated after calibration and saved by the vehicle after power-off.

[0058] III. Cooling System Oil Temperature Control Mode (Self-Learning and Updating), see [link / reference] Figure 4 :

[0059] 1. Reduce the second preset time T1: If the number of times the cooling system oil temperature control mode is satisfied exceeds the preset number (5000 times in this embodiment, and the number of times the cooling system oil temperature control mode is satisfied is immediately reset to zero after the preset time is updated), and no high-intensity knocking or pre-ignition occurs within the third preset time T2 after the cooling system oil temperature control mode is satisfied and exited, then the second preset time T1 is updated to 0.98 times the previous time. The second preset time T1 is reduced to ensure that the oil temperature rises as soon as possible and improves lubrication.

[0060] In this embodiment, if the second preset time T1 is updated a preset number of times, and the optimal embodiment takes 10 times, the first adjustment coefficient k1 and the second adjustment coefficient k2 are updated to 1.05 times the value before the update, but the final value after the update does not exceed 1.

[0061] 2. Add a second preset time T1: When the number of times the cooling system oil temperature control mode meets the preset number (5000 times in this embodiment, and the number of times the cooling system oil temperature control mode meets the preset number is immediately reset to zero after the preset time is updated), if the number of times high-intensity knocking occurs exceeds the preset number (1000 times in this embodiment) or the number of times pre-ignition occurs exceeds the preset number (20 times in this embodiment) within the third preset time T2 after the cooling system oil temperature control mode is exited, then the second preset time T1 is updated to 1.2 times the previous time, the second preset time T1 is increased, and engine protection is performed;

[0062] In this embodiment, if the second preset time T1 is updated a preset number of times, and in the optimal embodiment it is 10 times, the first adjustment coefficient k1 and the second adjustment coefficient k2 are updated to 0.9 times the value before the update, but the final value after the update is not less than 0.5, so as to avoid excessive water temperature drop and lubrication failure.

[0063] The purpose of updating the second preset time T1, the first adjustment coefficient k1, and the second adjustment coefficient k2 is to ensure engine lubrication by bringing the updated target water temperature as close as possible to the original target water temperature, in order to avoid high-intensity knocking or pre-ignition in the engine.

[0064] IV. Exiting the Cooling System Oil Temperature Control Mode: When exiting the cooling system oil temperature control mode, the target oil temperature will gradually return to the normal mode in a transitional manner. The transitional method is that, in this example, the target oil temperature changes at a maximum rate of 0.1℃ / 10ms.

[0065] The target oil temperature is adjusted according to the updated parameters. Based on the updated target oil temperature and the actual oil temperature, the oil temperature control actuator (such as the oil pump) is controlled to achieve the desired oil temperature.

[0066] See Figure 5 The present invention relates to a cooling system oil temperature control device, comprising the following components:

[0067] Cooling system oil temperature control start-up condition module: Whether to enter the cooling system oil temperature control mode is determined by whether four conditions are met: engine running time, engine knocking or pre-ignition, VVT control target phase deviation from actual phase, and ignition angle efficiency.

[0068] Calibration of target oil temperature adjustment parameters module: When entering the cooling system oil temperature control mode, the adjustment coefficient of the target oil temperature and the absolute value of the maximum rate of change of the adjustment coefficient of the target oil temperature are determined according to whether the piston cooling nozzle is open or not.

[0069] Cooling system oil temperature control mode module: If no high-intensity knocking or pre-ignition occurs within a certain period after the cooling system oil temperature control mode is met and exited, the time for the cooling system oil temperature control start-up condition change will be reduced to ensure that the oil temperature rises as quickly as possible; if the number of high-intensity knocking or pre-ignition exceeds the preset number within a certain period after the cooling system oil temperature control mode is exited, the time for the cooling system oil temperature control start-up condition change will be increased to protect the engine.

[0070] Exit the cooling system oil temperature control module: When exiting the cooling system oil temperature control mode, a transitional method is used to gradually restore the target oil temperature to the normal oil temperature.

[0071] The key technical points and technical principles of this invention are as follows:

[0072] 1) A target water temperature operating condition mode recognition method based on engine protection;

[0073] 2) Dynamic adjustment method for target oil temperature.

[0074] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0075] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A method for controlling the oil temperature of a cooling system, characterized in that: Includes the following steps: Cooling system oil temperature regulation activation conditions: Whether to enter the cooling system oil temperature regulation mode is determined by whether four conditions are met: engine running time, engine knocking or pre-ignition, VVT control target phase deviation from actual phase, and ignition angle efficiency. Calibrate the target oil temperature adjustment parameters: When entering the cooling system oil temperature control mode, determine the adjustment coefficient of the target oil temperature and the absolute value of the maximum rate of change of the adjustment coefficient of the target oil temperature based on whether the piston cooling nozzle is open or not. Cooling system oil temperature control mode: If no high-intensity knocking or pre-ignition occurs within a certain time after the cooling system oil temperature control mode is met and exited, the time for the cooling system oil temperature control start-up condition to change will be reduced to ensure that the oil temperature rises as quickly as possible. If high-intensity knocking or premature ignition exceeding the preset number occurs within a certain period after the cooling system oil temperature control mode is discontinued, the time for the cooling system oil temperature control activation condition to change will be increased to protect the engine.

2. The method for controlling the oil temperature of a cooling system according to claim 1, characterized in that: The specific process for initiating the cooling system oil temperature regulation is as follows: Basic conditions include four conditions: engine running time, high-intensity knocking or pre-ignition in the engine, deviation between the target phase and the actual phase in VVT control, and ignition angle efficiency. Conditions met: All basic conditions are met simultaneously; or, Conditions not fully met: The time from when all basic conditions are met to when not all basic conditions are met does not exceed the second preset time T1, and the engine's requested torque exceeds the product of the engine's maximum torque and the preset coefficient r1 for the first time after the above conditions are not met simultaneously. Startup judgment: When one of the conditions is met or not all conditions are met, the cooling system oil temperature control mode is entered.

3. The method for controlling the oil temperature of a cooling system according to claim 2, characterized in that: The specific content of the basic condition steps includes: Engine running time: The engine running time exceeds the first preset time T0; High-intensity knocking or pre-ignition: When high-intensity knocking or pre-ignition occurs in the engine; VVT control target phase: The deviation between the VVT ​​control target phase and the actual phase is within a preset range; Ignition angle efficiency: The ignition angle efficiency is not lower than the preset value.

4. The method for controlling the oil temperature of a cooling system according to claim 3, characterized in that: The specific steps for calibrating the target oil temperature adjustment parameters are as follows: Target oil temperature adjustment coefficient: The adjustment coefficient for the target oil temperature is determined by both engine speed and engine load. Specifically, when the piston cooling nozzle is open, the target oil temperature adjustment coefficient is the first adjustment coefficient k1; when the piston cooling nozzle is closed, the target oil temperature adjustment coefficient is the second adjustment coefficient k2. Maximum absolute value of the adjustment coefficient for target oil temperature: When the working state of the piston cooling nozzle is switched, the maximum absolute value of the adjustment coefficient for target oil temperature is determined by both engine speed and engine coolant temperature.

5. The method for controlling the oil temperature of a cooling system according to claim 4, characterized in that: In the step of calibrating the target oil temperature adjustment parameters, the calibration basis for the absolute value of the maximum change rate of the target oil temperature adjustment coefficient when the first adjustment coefficient k1, the second adjustment coefficient k2, and the piston cooling nozzle working state switch is that after entering the cooling system oil temperature control mode, regardless of whether the piston cooling nozzle is open, the engine torque is accurately controlled within ±5Nm, and the engine does not experience high-intensity knocking or pre-ignition.

6. The method for controlling engine oil temperature in a cooling system according to claim 5, characterized in that: The specific process of the cooling system oil temperature control mode is as follows: Reduce the second preset time T1: If the number of times the cooling system oil temperature control mode is satisfied exceeds the preset number, and no high-intensity knocking or pre-ignition occurs within the third preset time T2 after the cooling system oil temperature control mode is satisfied and exited, then reduce the second preset time T1. Add a second preset time T1: If the number of times the cooling system oil temperature control mode meets the preset number exceeds the preset number, and a high-intensity knocking or pre-ignition occurs within the third preset time T2 after the cooling system oil temperature control mode is exited, then add a second preset time T1.

7. The method for controlling engine oil temperature in a cooling system according to claim 6, characterized in that: In the step of reducing the second preset time T1, after the second preset time T1 is updated a preset number of times, the first adjustment coefficient k1 and the second adjustment coefficient k2 are updated to 1.00 to 1.1 times the value before the update, but the final value after the update does not exceed 1.

8. The method for controlling the oil temperature of a cooling system according to claim 7, characterized in that: In the step of increasing the second preset time T1, after the second preset time T1 is updated a preset number of times, the first adjustment coefficient k1 and the second adjustment coefficient k2 are updated to 0.8 to 1.0 times the value before the update, but the final value after the update is not less than 0.

5.

9. The method for controlling engine oil temperature in a cooling system according to claim 7, characterized in that: It also includes the step of exiting the cooling system oil temperature control mode. The specific process is as follows: when exiting the cooling system oil temperature control mode, a transitional method is used to gradually restore the target oil temperature to the normal oil temperature.

10. A cooling system oil temperature control device, comprising a computer program, characterized in that: The computer program is capable of executing the cooling system oil temperature control method as described in claims 1 to 9.

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