Start-up control method for electronic pumps in automotive hydraulic systems

Abstract

This invention provides a starting control method for an electronic pump in an automotive hydraulic system, comprising the following steps: S1: During the engine shutdown process of the automotive hydraulic system, a predicted pressure drop value is obtained based on a system pressure rise and fall model of the automotive hydraulic system. The system pressure rise and fall model is established based on the operating parameters of the automotive hydraulic system, including oil temperature, engine speed, and torque. S2: A pressure rise reference value is obtained based on a pressure build-up model of the electronic pump during the pressure build-up process of the automotive hydraulic system. The pressure build-up model is pre-established based on the operating parameters of the automotive hydraulic system during the pressure build-up process. S3: The starting time of the electronic pump is determined based on the predicted pressure drop value and the pressure rise reference value. By using the predicted pressure drop value and the pressure rise reference value to obtain the starting time of the electronic pump during the shutdown process of the mechanical pump, the electronic pump can be started in a timely and accurate manner.

Description

Technical Field

[0001] This invention relates to the automotive field, specifically to a method for starting and controlling an electronic pump in an automotive hydraulic system. Background Technology

[0002] For vehicles equipped with hydraulic actuators, when the mechanical pump is not working, the electronic pump (EOP) needs to be activated to provide a steady system working oil pressure or flow to ensure that the vehicle can continue to operate normally.

[0003] Especially in hybrid vehicles, when switching from hybrid or conventional operating mode to pure electric mode, the engine shuts off, and the mechanical pump can no longer provide the pressure or flow required by actuators such as shift forks or clutches. At this time, the electric pump (EOP) needs to be activated so that the clutch or shift forks can continue to shift up and down. However, the electric pump itself has its own operating boundary conditions and the electric pump has a certain response delay characteristics in building up system pressure. If it is activated too early, the bearings and shafts of the electric pump will be overloaded, which may lead to shaft or bearing breakage in severe cases. If it is activated too late, the performance will deteriorate at best, and the mechanical parts will fail seriously at worst. Especially for hybrid vehicles equipped with CVT transmissions, there is a risk of slippage and breakage of the steel belt system. Summary of the Invention

[0004] The purpose of this invention is to provide a starting control method for an electronic pump in an automotive hydraulic system. This method can accurately predict the starting timing of the electronic pump and replenish the system pressure and flow in a timely and reasonable manner during the shutdown of the mechanical pump. This ensures that the mechanical pump and the electronic pump can work well together, the system pressure is stable, and the hydraulic actuator can respond normally to the working requirements. In this way, the mechanical system can be protected and its service life can be improved while maintaining the vehicle's driving performance.

[0005] This invention provides a method for starting and controlling an electronic pump in an automotive hydraulic system, comprising the following steps:

[0006] S1: During engine shutdown in the automotive hydraulic system, the predicted pressure drop is obtained based on the system pressure rise and fall model of the automotive hydraulic system. This model is established based on the operating parameters of the automotive hydraulic system, including oil temperature, engine speed, and torque.

[0007] S2: Obtain the pressure rise comparison value of the automotive hydraulic system during the pressure build-up process based on the pressure build-up model of the electronic pump. The pressure build-up model is pre-established based on the operating parameters of the automotive hydraulic system during the pressure build-up process.

[0008] S3: Determine the start-up time of the electronic pump based on the predicted pressure drop value and the reference pressure rise value.

[0009] By adopting the above scheme, during the mechanical pump's shutdown process, without reducing the electronic pump's service life, the system pressure rise and fall model is used to obtain the predicted pressure drop value, and the pressure rise comparison value obtained from the pressure build-up model to determine the electronic pump's startup time. This ensures timely and accurate startup of the electronic pump, guaranteeing a smooth connection between the mechanical and electronic pumps, stable system pressure, and enabling the hydraulic actuator system to respond normally to operational demands. Furthermore, during the mechanical pump's shutdown process, without reducing the electronic pump's service life, the timely and accurate startup of the electronic pump ensures a smooth connection between the mechanical and electronic pumps, stable system pressure, and enables the hydraulic actuator system to respond normally to operational demands.

[0010] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a starting control method for an electronic pump in an automotive hydraulic system, which further includes, after step S3: S4: correcting the system pressure rise and fall model based on the deviation between the system target pressure and the actual system pressure after the electronic pump is started.

[0011] The above scheme utilizes the deviation between the actual pressure and the target pressure after the electronic pump starts to update and optimize in real time, so as to make predictions for the next start-up. Through online and real-time rolling optimization, the prediction accuracy is continuously improved.

[0012] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a starting control method for an electronic pump in an automotive hydraulic system. In step S4, the pressure reduction correction time during the engine shutdown process is obtained according to the deviation, and the pressure reduction correction time is used to cover the pressure drop prediction value.

[0013] Using the above scheme, with a certain efficiency of the electronic pump for oil filling and pressurization, the oil filling and pressurization time is directly proportional to the oil pressure. Based on the pressure deviation, it is possible to increase or decrease the oil filling time. Then, the pressure drop correction time is covered by the pressure drop prediction value so that the curve of the actual system pressure and the target system pressure are more consistent.

[0014] According to another specific embodiment of the present invention, an electronic pump start-up control method for an automotive hydraulic system is disclosed. The system pressure rise and fall model is established based on the time required for the system pressure to drop to a preset pressure threshold during the engine shutdown process under different operating parameter conditions. The preset pressure threshold is the minimum steel strip clamping pressure.

[0015] Using the above scheme, a model is obtained based on the relationship between time and pressure obtained from the pressure drop parameters, which is the time required for the system pressure to drop to the minimum steel strip clamping pressure. When using this model in actual vehicles, the time required for the current system pressure to drop to the preset pressure threshold can be directly obtained from the system pressure rise and fall model as the predicted pressure drop value.

[0016] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a starting control method for an electronic pump in an automotive hydraulic system. The pressure build-up model is established based on the pressure values ​​during the system pressure build-up process under different engine operating parameter conditions, and the pressure rise reference value is the time required for the system pressure to reach the minimum steel belt clamping pressure.

[0017] By adopting the above scheme, a pressure build-up model is established based on empirical or theoretical calculations of the time required for the system pressure to reach the minimum steel strip clamping pressure under different operating parameter conditions. This model obtains the time it takes for the pressure to rise to the minimum steel strip clamping pressure. Combined with the predicted time for the pressure to drop to the minimum steel strip clamping pressure, this ensures that when the pressure drops to the minimum steel strip clamping pressure after the mechanical pump stops working, the electronic pump completes the pressure build-up process and reaches the minimum steel strip clamping pressure. This allows the electronic pump to start in a timely and accurate manner, ensuring good connection between the mechanical pump and the electronic pump, stable system pressure, and enabling the hydraulic actuator system to respond normally to work requirements.

[0018] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a starting control method for an electronic pump in an automotive hydraulic system, wherein the pressure build-up model is pre-corrected based on the system oil filling model of the electronic pump at different temperatures.

[0019] By adopting the above scheme, after the pressure build-up model is built up and installed on the vehicle, the system oil-filled model can be used to correct the pressure build-up model on the actual vehicle, thereby improving the accuracy of the pressure build-up model.

[0020] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a starting control method for an electronic pump in an automotive hydraulic system. In step S3, the difference between the predicted pressure drop value and the control value for the pressure rise is compared. When the difference is less than a preset time threshold, the electronic pump is started.

[0021] By adopting the above scheme, deviations caused by manufacturing and control precision can be offset. The electronic pump is activated when the difference is less than a preset time threshold, so as to avoid delaying the start-up of the electronic pump.

[0022] The beneficial effects of this invention are:

[0023] This invention provides a method for starting an electronic pump in an automotive hydraulic system. During the shutdown of the mechanical pump, without reducing the lifespan of the electronic pump, the starting time of the electronic pump is determined by using a system pressure rise / fall model to obtain a predicted pressure drop value and a pressure rise comparison value obtained from a pressure build-up model. This method enables timely and accurate starting of the electronic pump, ensuring smooth operation between the mechanical and electronic pumps, stable system pressure, and allowing the hydraulic actuator system to respond normally to operational demands. Attached Figure Description

[0024] Figure 1 A control flow diagram of a starting control method for an electronic pump in an automotive hydraulic system provided in an embodiment of the present invention.

[0025] Figure 2 A block diagram illustrating the control principle of an electronic pump start-up control method for an automotive hydraulic system, provided in an embodiment of the present invention.

[0026] Figure 3 A schematic diagram of the hydraulic system structure of an electronic pump start-up control method for an automotive hydraulic system provided in an embodiment of the present invention;

[0027] Figure 4 A schematic diagram illustrating the effect of an electronic pump start-up control method for an automotive hydraulic system provided in an embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] Ⅰ: Electronic pump start command;

[0030] II: Engine speed;

[0031] III: Actual pressure;

[0032] IV: Target pressure;

[0033] 1: Electronic pump; 2: Electronic pump suction filter; 3: Mechanical pump; 4: Check valve; 5: Engine; 6: Mechanical pump suction filter; 7: Oil pan. Detailed Implementation

[0034] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0035] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0037] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0038] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0039] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0040] Example

[0041] This embodiment provides a method for starting and controlling an electronic pump in an automotive hydraulic system, such as... Figure 1 and Figure 2As shown, it includes the following steps:

[0042] S1: During engine shutdown in the automotive hydraulic system, the predicted pressure drop is obtained based on the system pressure rise and fall model of the automotive hydraulic system. This model is established based on the operating parameters of the automotive hydraulic system, including oil temperature, engine speed, and torque.

[0043] S2: Obtain the pressure rise comparison value of the automotive hydraulic system during the pressure build-up process based on the pressure build-up model of the electronic pump. The pressure build-up model is pre-established based on the operating parameters of the automotive hydraulic system during the pressure build-up process.

[0044] S3: Determine the start-up time of the electronic pump based on the predicted pressure drop value and the reference pressure rise value.

[0045] Specifically, the system pressure rise / fall model is used to predict the pressure drop during engine shutdown. The pressure build-up model can be tested under various operating parameters before vehicle installation to obtain the pressure-time relationship and serve as a reference for the pressure drop. Both the system pressure rise / fall model and the pressure build-up model reflect the pressure-time relationship, using the time point at which the actual hydraulic system pressure reaches a specific pressure as the predicted and reference values. Parameters during the system pressure drop under different automotive hydraulic system conditions (oil temperature, engine speed, and torque) are obtained through experiments or theoretical calculations. For example, when the pressure relief efficiency of the automotive hydraulic system is constant, the pressure drop time is proportional to the oil pressure; therefore, the time required for the system pressure to drop to a specific threshold can be used as the predicted pressure drop value. The system pressure rise / fall model can be a pre-established static model or a dynamically updated model. Preferred implementations of the specific system pressure rise / fall model and pressure build-up model will be described later and will not be repeated here. Furthermore, the specific threshold can be the minimum steel strip clamping pressure or other pressures; this implementation does not impose specific limitations here.

[0046] Figure 3 This is a schematic diagram of the hydraulic system. Figure 3 The components are labeled as follows: electronic pump 1, electronic pump filter 2, mechanical pump 3, check valve 4, engine 5, mechanical pump filter 6, and oil pan 7. When the mechanical pump is not working, the electronic pump (EOP) is activated to provide a stable hydraulic system working pressure or flow to ensure the vehicle can continue to operate normally.

[0047] Figure 4 From top to bottom, the signals are: electronic pump start control command I, engine speed II, actual pressure signal III, and target pressure signal IV. (Example) Figure 4The actual road verification results shown indicate that the actual pressure drop of the electronic pump is stable without fluctuations or differences. That is, the control method of this embodiment can continuously make predictive decisions based on vehicle information during the process of engine shutdown and engine speed reduction, and activate the electronic pump start command when the conditions are met. The actual vehicle test results show that the transition process between the mechanical pump and the electronic pump is well connected, and the pressure has no obvious fluctuations or differences, thus verifying that this embodiment is effective and feasible.

[0048] By adopting the above scheme, during the process of mechanical pump stopping work, without reducing the service life of electronic pump, the start-up time of electronic pump is obtained by using the pressure drop prediction value obtained by the system pressure rise and fall model and the pressure rise comparison value obtained by the pressure build-up model. This ensures that when the system pressure drops to a specific pressure, the electronic pump can just complete the pressure build-up process and provide that specific pressure, thereby enabling timely and accurate start-up of electronic pump. This ensures that mechanical pump and electronic pump can be well connected, system pressure is stable, and the hydraulic actuator system can respond normally to work requirements.

[0049] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a starting control method for an electronic pump in an automotive hydraulic system, such as... Figure 1 and Figure 2 As shown, after step S3, the method further includes: S4: Correcting the system pressure rise and fall model based on the deviation between the system target pressure and the actual system pressure after the electronic pump is started.

[0050] In this embodiment, the pressure rise and fall model is updated and optimized in real time, and the target pressure can be obtained from the hydraulic actuator.

[0051] The above scheme utilizes the deviation between the actual pressure and the target pressure after the electronic pump starts to update and optimize in real time, so as to make predictions for the next start-up. Through online and real-time rolling optimization, the prediction accuracy is continuously improved.

[0052] Furthermore, in step S4, the pressure reduction correction time of the engine during the shutdown process is obtained based on the deviation, and the pressure reduction correction time is used to cover the pressure reduction prediction value.

[0053] Specifically, given a fixed oil filling and pressurization efficiency of the electronic pump, the oil filling and pressurization time is directly proportional to the oil pressure. Based on the pressure deviation, it is possible to increase or decrease the oil filling time. Then, the pressure drop correction time is applied to cover the predicted pressure drop value so that the curves of the actual system pressure and the target system pressure are more consistent.

[0054] According to another specific embodiment of the present invention, an electronic pump start-up control method for an automotive hydraulic system is disclosed. The system pressure rise and fall model is established based on the time required for the system pressure to drop to a preset pressure threshold during the engine shutdown process under different operating parameter conditions. The preset pressure threshold is the minimum steel strip clamping pressure.

[0055] Using the above scheme, the operating parameters in this embodiment are engine speed, oil temperature, and torque. Pressure drop parameters, including the correspondence between time and pressure, are obtained during engine shutdown under different engine speed, oil temperature, and torque conditions based on experimental experience or theoretical calculations. Furthermore, a model is obtained based on the time-pressure correspondence of the pressure drop parameters to calculate the time required for the system pressure to drop to the minimum steel belt clamping pressure. When using this model in a real vehicle, the time required for the current system pressure to drop to a preset pressure threshold can be directly obtained from the system pressure rise and fall model as the predicted pressure drop value.

[0056] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a starting control method for an electronic pump in an automotive hydraulic system. The pressure build-up model is established based on the pressure values ​​during the system pressure build-up process under different engine operating parameter conditions, and the pressure rise reference value is the time required for the system pressure to reach the minimum steel belt clamping pressure.

[0057] Specifically, the operating parameters in this embodiment can be the engine target speed and system pressure, and a pressure build-up model can be established based on empirical values ​​or theoretical calculation values.

[0058] By adopting the above scheme, a pressure build-up model is established based on empirical or theoretical calculations of the time required for the system pressure to reach the minimum steel strip clamping pressure under different operating parameter conditions. This model obtains the time it takes for the pressure to rise to the minimum steel strip clamping pressure. Combined with the predicted time for the pressure to drop to the minimum steel strip clamping pressure, this ensures that when the pressure drops to the minimum steel strip clamping pressure after the mechanical pump stops working, the electronic pump completes the pressure build-up process and reaches the minimum steel strip clamping pressure. This allows the electronic pump to start in a timely and accurate manner, ensuring good connection between the mechanical pump and the electronic pump, stable system pressure, and enabling the hydraulic actuator system to respond normally to work requirements.

[0059] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a starting control method for an electronic pump in an automotive hydraulic system, wherein the pressure build-up model is pre-corrected based on the system oil filling model of the electronic pump at different temperatures.

[0060] By adopting the above scheme, after the pressure build-up model is built up and installed on the vehicle, the system oil-filled model can be used to correct the pressure build-up model on the actual vehicle, thereby improving the accuracy of the pressure build-up model.

[0061] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a starting control method for an electronic pump in an automotive hydraulic system. In step S3, the difference between the predicted pressure drop value and the control value for the pressure rise is compared. When the difference is less than a preset time threshold, the electronic pump is started.

[0062] Specifically, a decision model can be pre-established based on this control method. The decision model is used to make decisions on the output results of the system pressure rise and fall model and the pressure build-up model, determine whether the electronic pump needs to be started, and issue relevant instructions, namely, comparing the difference between the predicted pressure drop value and the control value of the pressure rise. When the difference is less than the preset time threshold, the electronic pump is started.

[0063] Furthermore, the preset time threshold can be selected according to the manufacturing process level and the actual vehicle requirements. When the manufacturing and control precision is high enough, the preset time threshold can be smaller. In other words, this embodiment can offset the deviation caused by manufacturing and control precision. When the difference is less than the preset time threshold, the electronic pump is turned on to avoid delaying the start-up timing of the electronic pump.

[0064] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A method for starting and controlling an electronic pump in an automotive hydraulic system, characterized in that, Includes the following steps: S1: During the engine shutdown process of the automotive hydraulic system, a predicted pressure drop value is obtained based on the system pressure rise and fall model of the automotive hydraulic system. This predicted pressure drop value is the time data required for the system pressure to drop to a preset pressure threshold. The system pressure rise and fall model is established based on the operating parameters of the automotive hydraulic system, including the oil temperature, engine speed, and torque of the automotive hydraulic system; the system pressure rise and fall model is established based on the time required for the system pressure to drop to the preset pressure threshold during the engine shutdown process under different operating parameter conditions, and the preset pressure threshold is the minimum steel strip clamping pressure; S2: Obtain the pressure rise reference value of the automotive hydraulic system during the pressure build-up process based on the pressure build-up model of the electronic pump. The pressure build-up model is established in advance based on the operating parameters of the automotive hydraulic system during the pressure build-up process. The pressure build-up model is established based on the pressure values ​​of the system pressure during the pressure build-up process under different operating parameter conditions of the engine. The pressure rise reference value is the time required for the system pressure to reach the minimum steel belt clamping pressure. S3: Determine the start-up time of the electronic pump based on the predicted pressure drop value and the reference pressure rise value, compare the difference between the predicted pressure drop value and the reference pressure rise value, and start the electronic pump when the difference is less than a preset time threshold.

2. The starting control method for an electronic pump in an automotive hydraulic system according to claim 1, characterized in that, The process after step S3 also includes: S4: Correct the system pressure rise and fall model based on the deviation between the system target pressure and the actual system pressure after the electronic pump is started.

3. The method for starting control of an electronic pump for an automotive hydraulic system according to claim 2, characterized in that, In step S4, the pressure reduction correction time during engine shutdown is obtained based on the deviation, and the pressure reduction correction time is used to cover the predicted pressure drop value.

4. The starting control method for an electronic pump in an automotive hydraulic system according to claim 1, characterized in that, The pressure build-up model was pre-corrected based on the system oil filling model of the electronic pump at different temperatures.

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