Intelligent control method and system for oil temperature of drive axle lubricating system

Abstract

The invention discloses an intelligent control method and system for the oil temperature of a drive axle lubricating system. The method comprises the steps that the target range T0 of the oil temperature of drive axle lubricating oil is set to be larger than or equal to 20 + / -2 DEG C and smaller than or equal to 100 + / -2 DEG C; detecting the temperature of each test point of the thermal management system, wherein the test points comprise a lubricating oil temperature T1 and a cooling liquid temperature T2; detecting the running state of the vehicle, and when an engine is ignited and the rotating speed of the vehicle is greater than 0m / s, activating a drive axle oil temperature intelligent control system; s4, under the condition that the drive axle oil temperature intelligent control system is activated, the following oil temperature control steps are executed: a) when T1 is smaller than 20 + / -2 DEG C, low-temperature control is executed; b) when T1 is greater than or equal to 100 + / -2 DEG C, executing high-temperature control; c) when the vehicle speed is less than or equal to 30km / h, executing low-speed working condition control; and d) when T2 is larger than T1, cooling liquid high-temperature control is executed. The problems that the drive axle assembly fails in advance, the torque transmission efficiency is reduced, and the oil temperature is low when a vehicle continues to be at a low speed are solved.

Description

Technical Field

[0001] The invention relates to a drive axle oil temperature control system and provides an intelligent control method and system for the oil temperature of a drive axle lubrication system. Background Art

[0002] In today's automotive engineering field, the drive axle lubrication system plays a vital role, which is directly related to the reliability of the drive axle and the economic performance of the whole vehicle. As a key component of the vehicle transmission system, the drive axle requires good lubrication conditions for its internal components during operation to ensure normal operation and reduce wear. The oil temperature in the lubrication system is a key factor, which has a direct and significant impact on the viscosity of the lubricant.

[0003] When the oil temperature is too high, the viscosity of the lubricating oil will become too high. This will cause a significant increase in the stirring loss of the assembly, just like stirring an object in a viscous liquid, which requires more energy and significantly reduces the efficiency of the assembly. During the operation of the vehicle, this excessively high oil temperature will not only affect the effective use of energy, but may also trigger a series of chain reactions, such as increasing the load on the engine, affecting the overall power performance and fuel economy of the vehicle.

[0004] On the contrary, when the oil temperature is too low, the viscosity of the lubricant will be too low. At this point, the lubricant's ability to resist impact loads is greatly reduced, just like a protective barrier that has lost sufficient toughness. In this case, the rotating parts inside the drive axle are susceptible to impact and wear. In the long run, it will cause early failure, seriously affecting the reliability and service life of the assembly. This poses a potential threat to the safe driving and long-term stable operation of the vehicle, and may lead to increased maintenance costs and reduced vehicle efficiency. The existing drive axle assembly completely relies on external air cooling for cooling, and is unable to actively adjust the internal oil temperature of the assembly, resulting in premature failure of the assembly and reduced assembly torque transmission efficiency; at the same time, it solves the problem that the oil temperature always fails to reach a reasonable operating temperature under the continuous low-speed operation of the vehicle. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method and system for intelligent oil temperature control of a drive axle lubrication system, which can achieve precise control of the oil temperature and ensure that the viscosity of the lubricating oil always remains within the optimal working range, thereby improving the reliability of the drive axle and the economy of the vehicle, and providing strong guarantee for the efficient and stable operation of the vehicle.

[0006] In order to achieve the above object, according to a first aspect of the present invention, a method for intelligently controlling oil temperature of a drive axle lubrication system is provided, comprising the following steps:

[0007] S1: Set the target range of the drive axle lubricating oil temperature to 20±2℃≤T0≤100±2℃;

[0008] S2: Detecting the temperature of each test point of the thermal management system, wherein the test points include the lubricating oil temperature T1 and the coolant temperature T2;

[0009] S3: Detect the vehicle running status. When the engine is ignited and the vehicle speed is greater than 0m / s, activate the intelligent control system of the drive axle oil temperature;

[0010] S4: When the drive axle oil temperature intelligent control system is activated, the following oil temperature control steps are performed:

[0011] a) When T1 is less than 20±2℃, low temperature control is performed;

[0012] b) When T1 is greater than or equal to 100±2℃, high temperature control is performed;

[0013] c) When the vehicle speed is less than or equal to 30km / h, low-speed operating condition control is executed;

[0014] d) When T2 is greater than T1, the coolant high temperature control is executed.

[0015] Furthermore, the low temperature control in step 4 includes: turning on the oil temperature heating module; when T2 is less than or equal to T1, keeping the cooling module turned off; when T1 reaches 20±2°C, turning off the heating module and the cooling module.

[0016] Furthermore, the high temperature control in step 4 includes: when T2 is less than T1, turning on the cooling module and starting the cooling fan; when T2 is greater than T1, turning off the cooling module until T2 is less than T1 and then turning on the cooling module again; when T1 reaches 100±2°C or T1 is less than or equal to T2, turning off the cooling module.

[0017] Furthermore, the low-speed operating condition control in step 4 includes: when the vehicle speed is less than or equal to 30 km / h and T1 is less than 60°C, the heating module is continuously turned on; when T1 is greater than or equal to 60°C, the heating module is turned off.

[0018] Furthermore, the high temperature control of the coolant in step 4 includes: when T2 is greater than T1, continuously turning on the cooling fan in the cooling module until T2 is less than or equal to T1, and then stopping the cooling fan.

[0019] Furthermore, the method also includes an adaptive temperature control method, which specifically includes the following steps:

[0020] (1) A temperature change model is established based on historical data. The temperature change model adopts the following mathematical expression:

[0021] T(k+1)=T(k)+α·ΔH(k)-β·ΔC(k)+γ·L(k)+ε(k)

[0022] in,

[0023] -T(k+1) is the predicted temperature at time k+1;

[0024] -T(k) is the actual temperature at time k;

[0025] -ΔH(k) is the rate of change of heating amount;

[0026] -ΔC(k) is the rate of change of cooling capacity;

[0027] -L(k) is the load factor;

[0028] -α, β, γ are the model parameters to be optimized;

[0029] -ε(k) is the temperature disturbance term;

[0030] (2) Use recursive least squares method to estimate model parameters online;

[0031] (3) Based on the optimized model parameters, the optimal control quantity is calculated using the model predictive control algorithm;

[0032] (4) Based on the system response effect, an adaptive adjustment algorithm is used to update the control parameters.

[0033] As another aspect of the present invention, it also relates to an intelligent oil temperature control system for a drive axle lubrication system, which also includes: a temperature detection module, used to detect the lubricating oil temperature T1 and the coolant temperature T2; a vehicle speed detection module, used to detect the vehicle running speed; a heating module, used to heat the lubricating oil; a cooling module, including a cooling device and a cooling fan; a controller, electrically connected to the temperature detection module, the vehicle speed detection module, the heating module and the cooling module, and used for the control method to perform oil temperature control.

[0034] Furthermore, the controller also includes: a system activation unit, which is used to control the activation state of the system according to the engine ignition signal and the vehicle speed signal; a temperature judgment unit, which is used to compare the detected temperature with a preset temperature range; and a mode selection unit, which is used to select to execute low temperature control, high temperature control or low speed operating condition control according to the temperature judgment result.

[0035] Furthermore, it also includes: an alarm module for issuing a warning signal when the lubricating oil temperature exceeds a preset range; and a display module for displaying the lubricating oil temperature, coolant temperature and system working status in real time.

[0036] Furthermore, the control signals of the heating module and the cooling module are PWM signals, which are used to achieve precise temperature control.

[0037] Furthermore, the temperature detection module includes: a first temperature sensor disposed in the lubricating oil cavity of the drive axle, for detecting the lubricating oil temperature T1; and a second temperature sensor disposed in the cooling module, for detecting the coolant temperature T2.

[0038] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0039] 1. The intelligent control system for the oil temperature of the drive axle of the present invention can avoid the problems of premature failure of the assembly and reduced torque transmission efficiency caused by excessively high or low oil temperature by intelligently controlling the temperature of the lubricating oil of the drive axle. The system can actively and adaptively adjust the internal oil temperature of the assembly to ensure that the viscosity of the lubricating oil remains within the optimal working range, thereby improving the reliability and efficiency of the assembly.

[0040] 2. The intelligent control system of the oil temperature of the drive axle of the present invention can ensure that the oil temperature reaches a reasonable operating temperature by controlling the strategy under the condition of continuous low speed of the vehicle, avoiding energy waste and reduced economy caused by too low oil temperature. By accurately controlling the oil temperature, the energy loss caused by improper oil temperature is reduced, and the economy of the whole vehicle is improved.

[0041] 3. The system of the present invention adopts efficient heating elements, such as ceramic heating elements and electromagnetic induction heating methods, to improve the heating speed and uniformity. At the same time, a temperature feedback control mechanism is added to ensure stable heating and no over-temperature. In addition, the heat dissipation structure of the cooling device is optimized to improve the heat dissipation efficiency. A high-performance cooling fan is selected to reduce noise and enhance reliability.

[0042] 4. The system of the present invention is also designed with a system activation unit for controlling the activation state of the system according to the engine ignition signal and the vehicle speed signal; a temperature judgment unit for comparing the detected temperature with a preset temperature range; and a mode selection unit for selecting to execute low temperature control, high temperature control or low speed operating condition control according to the temperature judgment result. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 : is a flow chart of a control method of a preferred embodiment of the present invention;

[0044] Figure 2 : is a control system flow chart of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] Please refer to Figure 1-Figure 2 The embodiment of the present invention provides a method for intelligently controlling oil temperature of a drive axle lubrication system, comprising the following steps:

[0047] 1. To ensure the lubrication performance of the drive axle, set the target temperature of the drive axle lubricating oil to 20±2℃≤T0≤100±2℃;

[0048] 2. Detect the temperature of each test point of the thermal management system;

[0049] 3. Detect the vehicle's operating status. When the engine is ignited and the vehicle speed is greater than 0m / s, the intelligent control system for the drive axle oil temperature is activated;

[0050] 4. When the lubricating oil temperature T1 is less than 20±2℃, the oil temperature heating module is turned on. At this time, if the coolant temperature of the cooling module T2≤T1, the cooling module remains closed. When T1 reaches the target oil temperature T0=20±2℃, the heating module is turned off; when the lubricating oil temperature T1 is less than 20±2℃, the oil temperature heating module is turned on. At this time, if the coolant temperature of the cooling module T2>T1, the cooling module is turned on. When T1 reaches the target oil temperature T0=20±2℃, the heating module and the cooling module are turned off;

[0051] 5. When the lubricating oil temperature T1 ≥ 100 ± 2 ° C, and the temperature of the cooling module coolant T2 < lubricating oil temperature T1, the cooling module is turned on: When the lubricating oil temperature T1 ≥ 100 ± 2 ° C, and the temperature of the cooling module coolant T2 > lubricating oil temperature T1, the solenoid valve in the cooling module remains closed, and the cooling fan is turned on to reduce the coolant medium temperature until the coolant temperature T2 < lubricating oil temperature T1, the cooling module is turned on; when the lubricating oil T1 reaches the target oil temperature TO = 100 ± 2 ° C, or the lubricating oil temperature T1 ≤ the coolant temperature T2, the cooling module is closed:

[0052] 6. When the vehicle is in a continuous low-speed condition, the speed n≤30km / h, set the drive axle lubricating oil temperature T1≥60℃, otherwise the heating module will continue to work to ensure that the oil temperature is within a reasonable range;

[0053] As another aspect of the present invention, some embodiments also relate to an intelligent control system for drive axle oil temperature, including a temperature detection module, a heating module, a cooling module, a vehicle speed detection module, a controller, an alarm module and a display module.

[0054] The temperature detection module includes: a first temperature sensor arranged in the lubricating oil cavity of the drive axle, used for detecting the lubricating oil temperature T1; a second temperature sensor arranged in the cooling module, used for detecting the coolant temperature T2; a cooling module and a heating module, used for adjusting the lubricating oil in the drive axle; the cooling module, including a cooling device and a cooling fan; an oil temperature intelligent control module, used for receiving the temperature information fed back by the oil temperature detection module, and controlling the solenoid valve of the cooling module and the relay of the heating module of the controlled object, and controlling the operation of the cooling module and the heating module according to the oil temperature control range; the oil temperature detection module is used for collecting the cooling medium temperature of the cooling module and the oil temperature inside the drive axle, and feeding back the oil temperature information to the oil temperature intelligent control module; a vehicle speed detection module, used for detecting the running speed of the vehicle; a controller, electrically connected to the temperature detection module, the vehicle speed detection module, the heating module and the cooling module, used for the control method to execute oil temperature control; an alarm module, used for issuing a warning signal when the lubricating oil temperature exceeds a preset range; a display module, used for displaying the lubricating oil temperature, the coolant temperature and the system working status in real time.

[0055] In the preferred embodiment, for the heating module, efficient heating elements, such as ceramic heating elements and electromagnetic induction heating methods, are used to improve the heating speed and uniformity. At the same time, a temperature feedback control mechanism is added to ensure stable heating and no over-temperature. In the cooling module, the heat dissipation structure of the cooling device is optimized to improve the heat dissipation efficiency. A high-performance cooling fan is selected to reduce noise and enhance reliability. In addition, it is possible to consider setting up independent protection devices for the heating module and the cooling module to prevent damage to the system due to abnormal conditions.

[0056] In some embodiments, as a preferred solution, the controller also includes: a system activation unit, used to control the activation state of the system according to the engine ignition signal and the vehicle speed signal; a temperature judgment unit, used to compare the detected temperature with a preset temperature range; a mode selection unit, used to select to execute low temperature control, high temperature control or low speed operating condition control according to the temperature judgment result.

[0057] The control signals of the heating module and the cooling module are preferably PWM signals, which are used to achieve precise temperature control.

[0058] In the preferred embodiment, in order to improve the temperature control accuracy, a high-precision temperature sensor with fast response and accurate measurement performance is used. An intelligent temperature compensation algorithm is set to automatically adjust the control parameters according to environmental changes. The temperature control logic of the controller is optimized to achieve more precise temperature regulation. At the same time, a temperature monitoring feedback mechanism is established to correct the control deviation in real time to ensure that the oil temperature is always within the precise control range.

[0059] In the preferred embodiment, in order to ensure the stability of the system operation, the system fault diagnosis and self-repair functions are added. When the temperature detection module, heating module, cooling module, etc. fail, the system can detect the failure in time and issue an alarm, and try to perform self-repair or take emergency measures to ensure the normal operation of the drive axle. For example, a backup temperature sensor or heating / cooling device can be set to automatically switch to the backup device when the main device fails.

[0060] In some other embodiments, in order to improve control accuracy, automatically compensate for changes in system parameters, and reduce steady-state errors; improve temperature control stability, improve system reliability, and avoid excessively high or low temperatures, for example, when the temperature difference from the target temperature is large, perform rapid heating or cooling, and when the temperature is close to the target temperature, perform slow heating or cooling; a sub-adaptive temperature control method is also proposed, which specifically includes the following steps:

[0061] 1. A temperature change model is established based on historical data. The temperature change model uses the following mathematical expression:

[0062] T(k+1)=T(k)+α·ΔH(k)-β·ΔC(k)+γ·L(k)+ε(k)

[0063] Where: T(k+1) is the predicted temperature at time k+1; T(k) is the actual temperature at time k; ΔH(k) is the rate of change of heating; ΔC(k) is the rate of change of cooling; L(k) is the load factor; α, β, γ are the model parameters to be optimized; ε(k) is the temperature disturbance term.

[0064] 2. Use the recursive least squares method to estimate the model parameters online. The parameter update formula is as follows:

[0065] θ(k)=θ(k-1)+P(k)·φ(k)·[y(k)-φT(k)·θ(k-1)]P(k)=P(k-1)-P(k-1)·φ(k)·φT(k)·P(k-1) / [1+φT(k)·P(k-1)·φ(k)]

[0066] Among them, θ(k)=[α,β,γ]T is the parameter vector; P(k) is the covariance matrix; φ(k)=[ΔH(k),ΔC(k),L(k)]T is the regression vector; y(k) is the actual measured temperature change value.

[0067] 3. Based on the optimized model parameters, the model predictive control algorithm is used to calculate the optimal control quantity, and the control objective function is:

[0068] J=Σ[w1·(T(k+i)-Tref)2+w2·ΔH(k+i)2+w3·ΔC(k+i)2]

[0069] Wherein, Tref is the target temperature; w1, w2, w3 are weight coefficients; i is the prediction step length;

[0070] Solve the optimal control sequence under the following constraints:

[0071] ΔHmin≤ΔH(k)≤ΔHmax

[0072] ΔCmin≤ΔC(k)≤ΔCmax

[0073] |T(k)-Tref|≤ΔTmax

[0074] 4. According to the system response effect, the adaptive adjustment algorithm is used to update the control parameters. The adjustment rules are as follows:

[0075] w1(k+1)=w1(k)+μ1·|T(k)-Tref|

[0076] w2(k+1)=w2(k)+μ2·|ΔH(k)|

[0077] w3(k+1)=w3(k)+μ3·|ΔC(k)|

[0078] Among them, μ1, μ2, and μ3 are learning rate parameters;

[0079] When the control effect meets the requirements, the learning rate parameter is gradually reduced:

[0080] μi(k+1)=λ·μi(k),0<λ<1,i=1,2,3

[0081] The following example illustrates (taking low-speed conditions as an example): Assume that the vehicle is running at a low speed (speed ≤ 30 km / h):

[0082] Initial state: Current oil temperature: 25°C, target temperature: 60°C (minimum requirement for low-speed operation).

[0083] Initial load: Normal load.

[0084] Stage 1 (rapid heating): The system detects a large temperature difference (60-25 = 35°C), the adaptive controller gives a larger heating control amount, and the heating module works at full power;

[0085] The second stage (transition regulation) with a faster temperature rise rate: when the temperature rises to about 45°C, the system automatically reduces the heating power and the controller parameters are adjusted adaptively;

[0086] Moderate temperature rise rate Stage 3 (fine adjustment): The temperature is close to the target value of 58-62°C, and the controller enters the fine adjustment mode, dynamically adjusting according to load changes to keep the temperature within the target range.

[0087] The intelligent control system for the oil temperature of the drive axle of the present invention can avoid the problems of premature failure of the assembly and reduced torque transmission efficiency caused by excessively high or low oil temperature by intelligently controlling the temperature of the lubricating oil of the drive axle. The system can actively and adaptively adjust the internal oil temperature of the assembly to ensure that the viscosity of the lubricating oil remains within the optimal working range, thereby improving the reliability and efficiency of the assembly.

[0088] The intelligent control system for the oil temperature of the drive axle of the present invention can ensure that the oil temperature reaches a reasonable operating temperature by controlling the strategy under the condition of continuous low speed of the vehicle, thereby avoiding energy waste and reduced economy caused by too low oil temperature. By accurately controlling the oil temperature, energy loss caused by improper oil temperature is reduced, and the economy of the whole vehicle is improved.

[0089] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for intelligently controlling oil temperature of a drive axle lubrication system, characterized in that: The following steps are involved: S1: Set the target range of the drive axle lubricating oil temperature to 20±2℃≤T0≤100±2℃; S2: Detecting the temperature of each test point of the thermal management system, wherein the test points include the lubricating oil temperature T1 and the coolant temperature T2; S3: Detect the vehicle running status. When the engine is ignited and the vehicle speed is greater than 0m / s, activate the intelligent control system of the drive axle oil temperature; S4: When the drive axle oil temperature intelligent control system is activated, the following oil temperature control steps are performed: a) When T1 is less than 20±2℃, low temperature control is performed; b) When T1 is greater than or equal to 100±2℃, high temperature control is performed; c) When the vehicle speed is less than or equal to 30km / h, low-speed operating condition control is executed; d) When T2 is greater than T1, high-temperature coolant control is performed.

2. The intelligent oil temperature control method of the drive axle lubrication system according to claim 1 is characterized in that: The low temperature control in step 4 includes: Turn on the oil heating module; When T2 is less than or equal to T1, the cooling module is kept turned off; When T1 reaches 20±2℃, turn off the heating module and the cooling module.

3. The intelligent oil temperature control method of the drive axle lubrication system according to claim 1 is characterized in that: The high temperature control in step 4 includes: When T2 is less than T1, the cooling module is turned on and the cooling fan is started; When T2 is greater than T1, the cooling module is turned off and the cooling module is turned on again when T2 is less than T1; When T1 reaches 100±2℃ or T1 is less than or equal to T2, turn off the cooling module.

4. The intelligent oil temperature control method of the drive axle lubrication system according to claim 1 is characterized in that: The low speed operating condition control in step 4 includes: When the vehicle speed is less than or equal to 30km / h and T1 is less than 60℃, the heating module is continuously turned on; When T1 is greater than or equal to 60°C, the heating module is turned off.

5. The intelligent oil temperature control method of the drive axle lubrication system according to claim 1 is characterized in that: Coolant high temperature control in step 4: When T2 is greater than T1, the cooling fan in the cooling module is continuously turned on until T2 is less than or equal to T1, at which time the cooling fan stops.

6. The intelligent oil temperature control method of the drive axle lubrication system according to claim 1 is characterized in that: It also includes an adaptive temperature control method, which specifically includes the following steps: (1) A temperature change model is established based on historical data. The temperature change model adopts the following mathematical expression: T(k+1)=T(k)+α·ΔH(k)-β·ΔC(k)+γ·L(k)+ε(k) in, T(k+1) is the predicted temperature at time k+1; T(k) is the actual temperature at time k; ΔH(k) is the rate of change of heating amount; ΔC(k) is the rate of change of cooling capacity; L(k) is the load factor; α, β, and γ are the model parameters to be optimized; ε(k) is the temperature disturbance term; (2) Use recursive least squares method to estimate model parameters online; (3) Based on the optimized model parameters, the optimal control quantity is calculated using the model predictive control algorithm; (4) Based on the system response effect, an adaptive adjustment algorithm is used to update the control parameters.

7. An intelligent oil temperature control system for a drive axle lubrication system, characterized in that: include: A temperature detection module is used to detect the lubricating oil temperature T1 and the coolant temperature T2; Vehicle speed detection module, used to detect vehicle running speed; A heating module, used for heating the lubricating oil; A cooling module, including a cooling device and a cooling fan; A controller is electrically connected to the temperature detection module, the vehicle speed detection module, the heating module and the cooling module, and is used to perform oil temperature control according to the control method described in any one of claims 1 to 6.

8. The intelligent oil temperature control system for the drive axle lubrication system according to claim 7 is characterized in that: The controller further comprises: A system activation unit, used to control the activation state of the system according to an engine ignition signal and a vehicle speed signal; A temperature determination unit, used to compare the detected temperature with a preset temperature range; The mode selection unit is used to select low-temperature control, high-temperature control or low-speed operating condition control according to the temperature judgment result.

9. The intelligent oil temperature control system for the drive axle lubrication system according to claim 8 is characterized in that: Also includes: An alarm module is used to send out a warning signal when the lubricating oil temperature exceeds a preset range; Display module, used to display lubricating oil temperature, coolant temperature and system working status in real time; The control signals of the heating module and the cooling module are PWM signals, which are used to achieve precise temperature control.

10. The intelligent oil temperature control system for the drive axle lubrication system according to claim 5, characterized in that: The temperature detection module comprises: A first temperature sensor disposed in the lubricating oil cavity of the drive axle, for detecting the lubricating oil temperature T1; The second temperature sensor disposed in the cooling module is used to detect the coolant temperature T2.

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