A control method for an engine target oil pressure
By monitoring the temperature difference between the atmosphere and the water temperature and adjusting the oil pressure, combined with VVT control and self-learning correction factors, the target oil pressure of the engine is optimized, which solves the problem of control accuracy and robustness of the engine when pressure changes, and improves the engine's power and lifespan.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DONGFENG MOTOR GRP
- Filing Date
- 2023-09-13
- Publication Date
- 2026-06-23
AI Technical Summary
Existing technologies suffer from low closed-loop control accuracy and poor robustness when the target engine oil pressure varies significantly, leading to unstable engine performance.
By monitoring the difference between atmospheric temperature and engine coolant temperature, the target oil pressure is adjusted. Combined with variable valve timing (VVT) control, the oil pressure control method is optimized, including self-learning correction factors and filtering algorithms, to ensure the engine's power and safety under different operating conditions.
It improves the closed-loop control accuracy and robustness of the engine under different operating conditions, enhances the engine's power, economy and lifespan, and avoids engine component aging and performance degradation caused by oil pressure fluctuations.
Smart Images
Figure CN117145604B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of engine control technology, specifically relating to a method for controlling the target oil pressure of an engine. Background Technology
[0002] An engine is a power source that converts chemical energy into mechanical energy through combustion, generating a large amount of heat energy in the process. From the perspectives of power, economy, and emissions performance, an engine is best operated at its optimal pressure.
[0003] Setting the target oil pressure for an engine is crucial for its power, fuel economy, and lifespan. Patent CN202010523747.0 discloses a control method and system for a variable displacement oil pump in vehicles. This method primarily determines the deviation influence factor, overshoot influence factor, and steady-state influence factor based on the difference between the target oil pressure and the actual oil pressure; calculates the P-term control percentage and D-term control percentage; calculates the I-term control percentage based on the feedforward control duty cycle, the P-term control percentage, the D-term control percentage, and the I-term control percentage from the previous moment; and uses the sum of the feedforward control duty cycle, the P-term control percentage, the D-term control percentage, and the I-term control percentage as the oil pump duty cycle. This patent sets the target oil pressure for different operating conditions and improves the responsiveness and accuracy of the oil pressure closed-loop control through a "feedforward + PID" control method. However, when the target oil pressure changes significantly, the closed-loop control exhibits low accuracy and poor robustness. Therefore, a new method for controlling the target oil pressure of an engine is proposed. Summary of the Invention
[0004] The purpose of this invention is to provide a method for controlling the target oil pressure of an engine, thereby solving the problems of low closed-loop control accuracy and poor robustness when the target oil pressure of the engine changes significantly.
[0005] The technical solution adopted in this invention is as follows:
[0006] A method for controlling a target engine oil pressure includes the following steps:
[0007] When the atmospheric temperature T Ambient With engine coolant temperature T CoolantAct The difference T Err When the temperature exceeds the first preset temperature T1, the oil pressure is adjusted according to the original target oil pressure p. OilInt The adjustment characteristic value k of the target oil pressure and the atmospheric temperature T Ambient With engine coolant temperature T CoolantAct The difference T Err Determine the target oil pressure p OilDsrd ;
[0008] When the engine coolant temperature TCoolantAct With atmospheric temperature T Ambient The difference T CoolantErr When the temperature exceeds the second preset temperature T2, the oil pressure is adjusted according to the original target oil pressure p. OilInt The adjustment characteristic value k of the target oil pressure and the engine coolant temperature T CoolantAct With atmospheric temperature T Ambient The difference T CoolantErr Determine the target oil pressure p OilDsrd ;
[0009] If either of the above two conditions is met, then the final target oil pressure p OilDsrdFinal equal to target oil pressure p OilDsrd Otherwise, based on the final target oil pressure of the previous moment, the fixed update cycle Δt, the filtering time T, and the original target oil pressure p at this moment... OilInt Determine the final target oil pressure p at this moment. OilDsrdFinal .
[0010] Furthermore, based on the original target oil pressure p OilInt The adjustment characteristic value k of the target oil pressure and the atmospheric temperature T Ambient With engine coolant temperature T CoolantAct The difference T Err Determine the target oil pressure p OilDsrd for:
[0011] p OilDsrd =p OilInt +max{0,min[f1(p OilInt ,k),f1(p OilInt ,T Err )]}
[0012] In the formula, f1(p OilInt k) is determined by the original target oil pressure p OilInt The adjustment characteristic value k of the target oil pressure was obtained through calibration. The calibration was based on the following conditions: the engine did not experience high-intensity knocking, the engine's firing torque accuracy was within the preset firing torque accuracy range, the wheel-end torque accuracy was within the preset wheel-end torque accuracy range, the engine coolant temperature accuracy was within the preset coolant temperature range, and the variable valve timing (VVT) control accuracy was not reduced compared to the VVT control accuracy before oil pressure adjustment; f1(p OilInt ,T Err It is obtained by calibration based on the original target oil pressure and the difference between atmospheric temperature and engine coolant temperature. The calibration is based on the minimum oil pressure at which the oil temperature cannot be reduced under different atmospheric temperature and engine coolant temperature differences.
[0013] Furthermore, the preset accuracy range of the fire circuit torque is within ±5%, the preset accuracy range of the wheel end torque is within ±5%, and the preset accuracy range of the water temperature is within ±2.5℃.
[0014] Furthermore, based on the original target oil pressure p OilInt The adjustment characteristic value k of the target oil pressure and the engine coolant temperature T CoolantAct With atmospheric temperature T Ambient The difference T CoolantErr Determine the target oil pressure p OilDsrd for:
[0015] p OilDsrd =p OilInt +max{0,max[f2(p OilInt ,k),f2(p OilInt ,T CoolantErr )]}
[0016] In the formula, f2(p OilInt k) is determined by the original target oil pressure p OilInt The adjustment characteristic value k of the target oil pressure was obtained through calibration. The calibration was based on the following conditions: the engine did not experience high-intensity knocking, the engine's firing torque accuracy was within the preset firing torque accuracy range, the wheel-end torque accuracy was within the preset wheel-end torque accuracy range, the engine coolant temperature accuracy exceeded the preset coolant temperature accuracy range for no more than a preset continuous time, and the variable valve timing (VVT) control accuracy did not decrease compared to the VVT control accuracy before oil pressure adjustment; f2(p OilInt ,T CoolantErr The calibration is obtained by measuring the original target oil pressure and the difference between engine coolant temperature and ambient temperature. The calibration is based on the fact that the continuous time during which the engine coolant temperature accuracy exceeds the preset coolant temperature accuracy under different engine coolant temperature and ambient temperature differences does not exceed the preset continuous time.
[0017] Furthermore, the preset accuracy range of the fire circuit torque is within ±5%, the preset accuracy range of the wheel end torque is within ±5%, the preset accuracy range of the water temperature is within ±2.5℃, and the preset continuous time is 0.5s.
[0018] Furthermore, based on the final target oil pressure at the previous moment, the fixed update cycle Δt, the filtering time T, and the original target oil pressure p at this moment... OilInt Determine the final target oil pressure p at this moment. OilDsrdFinal for:
[0019]
[0020] In the formula, p OilDsrdFinal (N) represents the final target oil pressure at time N, p OilDsrdFinal(N-1) represents the final target oil pressure at time N-1. Specifically, when N=1, p OilDsrdFinal (0) equals the target oil pressure p at the previous moment. OilDsrd The time difference between time N-1 and time N is a fixed update period Δt, p OilInt (N) represents the original target oil pressure at time N, where N = 1, 2, 3...
[0021] Furthermore, the calculation method for the target oil pressure adjustment characteristic value k is as follows:
[0022]
[0023] In the formula, M Sprk Req M represents the requested / target torque value for the fire circuit. AirAct T represents the actual value of the air circuit torque. CoolantErr M represents the difference between the target water temperature and the actual water temperature. Max For the engine's maximum torque, dr SprkEff Engine ignition angle efficiency r SprkEff rate of change, SOC Diff M represents the difference between the target SOC and the current actual SOC of the high-voltage power battery. WheelTrq Req M requests torque at the wheel ends of the entire vehicle. WheelTrqAct r represents the actual torque at the wheel end of the entire vehicle. Adp This is a self-learning correction factor;
[0024] First calibration It is in the engine ignition angle efficiency r SprkEff rate of change dr SprkEff Within the preset fluctuation range and the difference between the target SOC and the current actual SOC of the high-voltage power battery Diff The calibration was performed based on a preset SOC range.
[0025] Then calibrate It is the difference between the target SOC and the current actual SOC of the high-voltage power battery. Diff The calibration was performed based on a preset SOC range.
[0026] Final calibration SOC Diff The larger, The larger, the better The larger.
[0027] Furthermore, the self-learning correction factor r Adp The update is as follows:
[0028] During each driving cycle of the vehicle, the self-learning correction factor r Adp It will only be updated once at most, and the self-learning conditions are:
[0029] (1) The engine is running;
[0030] (2) The engine did not experience high-intensity knocking;
[0031] (3) The accuracy of the engine's firing circuit torque is within the preset firing circuit torque accuracy range;
[0032] (4) The accuracy of the wheel end torque of the whole wheel is within the preset wheel end torque accuracy range;
[0033] (5) The vehicle mileage since the last target oil pressure self-learning correction factor update exceeds the preset mileage value;
[0034] If all of the above conditions are met:
[0035] 1) If the engine coolant temperature accuracy is maintained within the preset coolant temperature accuracy range, and the continuous time for which the variable valve timing (VVT) control accuracy exceeds the preset control accuracy range exceeds the preset time t1, then the target oil pressure self-learning correction factor is increased by C1.
[0036] 2) If the engine coolant temperature accuracy exceeds the preset coolant temperature accuracy range and the target coolant temperature is not greater than the actual coolant temperature, and its continuous time exceeds the preset time t2, and the variable valve timing (VVT) control accuracy is always maintained within the preset control accuracy range, then the target oil pressure self-learning correction factor is increased by C2.
[0037] 3) If the engine coolant temperature accuracy exceeds the preset coolant temperature accuracy range and the target coolant temperature is greater than the actual coolant temperature, and its continuous time exceeds the preset time t1, and the variable valve timing (VVT) control accuracy is maintained within the preset control accuracy range, then the target oil pressure self-learning correction factor is reduced by C3.
[0038] 4) If the engine coolant temperature accuracy exceeds the preset coolant temperature accuracy range and the target coolant temperature is not greater than the actual coolant temperature, and its continuous time exceeds the preset time t2, and the time when the variable valve timing (VVT) control accuracy exceeds the preset control accuracy range exceeds the preset time t1, then the target oil pressure self-learning correction factor is added to C4; where C2 is less than C1 and less than C4.
[0039] 5) Under other circumstances, the target oil pressure self-learning correction factor remains unchanged during this learning process.
[0040] Furthermore, the initial determination of the first preset temperature T1 depends on the oil temperature T. Oil With engine coolant temperature T CoolantAct The difference T OilErr Difference T OilErr The larger the value, the larger the first preset temperature T1, and then it is updated through self-learning; the initial determination of the second preset temperature T2 depends on the oil temperature T. OilWith engine coolant temperature T CoolantAct The difference T OilErr Difference T OilErr The larger the value, the smaller the second preset temperature T2, and then it will be updated through self-learning.
[0041] Furthermore, the self-learning updates of the first preset temperature T1 and the second preset temperature T2 include:
[0042] Get the learning value r Adp The number of consecutive increases CNT1, and the learning value r Adp The number of consecutive decreases (CNT2), the first preset temperature (T1), the second preset temperature (T2), and the learning value (r) Adp Update the ambient temperature and actual engine coolant temperature at the current moment; if:
[0043] 1) Learning value r Adp The atmospheric temperature at the update time is greater than the learning value r. Adp If the actual engine coolant temperature at the time of update is found, and CNT1 exceeds the preset value, then the first preset temperature T1 is updated to 1.01 times the value of the last update, and CNT1 is immediately cleared to zero.
[0044] 2) Learning value r Adp The atmospheric temperature at the update time is greater than the learning value r. Adp If the actual engine coolant temperature at the time of update is found, and CNT2 exceeds the preset value, then the first preset temperature T2 will be updated to 0.98 times the value of the last update, and CNT2 will be immediately cleared to zero.
[0045] 3) Learning value r Adp The atmospheric temperature at the update time is no greater than the learning value r. Adp If the actual engine coolant temperature at the time of update is found and CNT2 exceeds the preset value, then the first preset temperature T2 will be updated to 1.015 times the value of the last update, and CNT2 will be immediately cleared to zero.
[0046] 4) Learning value r Adp The atmospheric temperature at the update time is no greater than the learning value r. Adp If the actual engine coolant temperature at the time of update is found and CNT1 exceeds the preset value, then the first preset temperature T1 will be updated to 0.975 times the value of the last update, and CNT1 will be immediately cleared to zero.
[0047] 5) Under other circumstances, the first preset temperature T1 and the second preset temperature T2 are not updated.
[0048] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0049] This invention relates to a target oil pressure control method based on engine VVT performance, engine knock protection, engine torque performance, and vehicle torque performance. It also avoids control parameter deviations caused by engine component aging and is applicable to parameter self-tuning after the engine's life cycle has progressed. Attached Figure Description
[0050] Figure 1 This is a flowchart of the engine target oil pressure control method according to an embodiment of the present invention. Detailed Implementation
[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.
[0052] This invention proposes a method for controlling the target oil pressure of an engine, which mainly achieves the oil pressure requirement by controlling a variable displacement oil pump. By improving the target oil pressure, the requirements for power, economy, and safety protection under different vehicle operating conditions can be met.
[0053] This invention primarily optimizes the target oil pressure during engine operation. First, it proposes the original target oil pressure p. OilInt The concept refers to the target oil pressure currently disclosed. For details, please refer to the setting of the target oil pressure during engine operation in patent CN202010523747.0, "A control method and system for a variable displacement oil pump for vehicles".
[0054] The engine target oil pressure control method of this invention embodiment, such as... Figure 1 As shown, it includes:
[0055] 1) When the atmospheric temperature T Ambient With engine coolant temperature T CoolantAct The difference T Err When the temperature exceeds the preset temperature T1 (e.g., when the ambient temperature is higher than the engine coolant temperature, such as when a vehicle moves from a relatively cold, enclosed space to an open outdoor environment), in this example, we take 5°C, then the target oil pressure p OilDsrd for:
[0056] p OilDsrd =p OilInt +max{0,min[f1(p OilInt ,k),f1(p OilInt ,T Err )]}
[0057] In the formula, T Err The difference between atmospheric temperature and engine coolant temperature is denoted as k; k is the target oil pressure adjustment characteristic value. The larger the target oil pressure adjustment characteristic value k is, the greater the target oil pressure correction will be. This will be discussed in detail later. The main purpose is to improve the target oil pressure from the perspective of improving thermal management performance and avoiding knocking.
[0058] When the temperature difference between the ambient temperature and the engine coolant temperature is too large, excessively increasing the oil pressure will not dissipate the heat of the coolant into the atmosphere. Instead, it will increase the power consumption of the oil pump due to the increased pressure. Therefore, the target oil pressure can be limited.
[0059] Where f1(p) OilInt ,T Err The calibration is based on different atmospheric temperatures and engine coolant temperature differences (T). Err The minimum oil pressure at which the oil temperature cannot be reduced (the method to determine that the oil temperature cannot be reduced is that the rate of change of the oil temperature under the current oil pressure is not less than 0℃ / s) is calibrated as shown in Table 1 in this example.
[0060] Table 1f1(p OilInt ,T Err Calibration table
[0061]
[0062] Target oil pressure adjustment characteristic values k and f1(p) OilInt The method for determining the target oil pressure adjustment characteristic value k is as follows: The larger the target oil pressure adjustment characteristic value k, the greater the target oil pressure correction. Its calibration is based on the following conditions: under these conditions, the engine does not experience high-intensity knocking (high-intensity knocking refers to knocking that causes a delay in ignition angle exceeding 6° crankshaft angle), and the engine's firing torque accuracy (engine firing torque accuracy refers to the difference between the engine's requested firing torque and the actual firing torque divided by the engine's requested firing torque) is within ±5%, and the wheel-end torque accuracy (wheel-end torque accuracy refers to the difference between the requested torque at the wheel end...) is within ±5%. The difference between the actual torque at the wheel end and the requested torque at the wheel end is within ±5%, and the engine coolant temperature accuracy (i.e., the difference between the target coolant temperature and the actual coolant temperature) is within ±2.5℃. Furthermore, the VVT (Variable Valve Timing) control accuracy is not reduced compared to the VVT control accuracy before oil pressure adjustment (VVT control accuracy refers to the difference between the target VVT phase and the actual VVT phase divided by the target VVT phase). This means that the VVT control accuracy after adjusting the target oil pressure is equivalent to or even improved compared to the VVT control accuracy without adjusting the target oil pressure. The calibration for this example is shown in Table 2.
[0063] Table 2f1(p) OilInt ,k) Calibration Table
[0064]
[0065] The determination of T1 depends on the oil temperature T. Oil With engine coolant temperature T CoolantAct The difference T OilErr The larger the difference, the more necessary it is to limit the increase in oil pressure to prevent the oil temperature from rising further and thus hindering heat transfer. The preset temperature T1 and below are calibration values set during vehicle development. These values will be continuously updated through self-learning at different stages of the vehicle's lifecycle after mass production and can be stored after power-off. The calibration in this example is shown in Table 3.
[0066] Table 3T1 Calibration Table
[0067] <![CDATA[T OilErr (℃)]]> -10 -8 -6 -3 0 2 T1(℃) 0 2 3 4 5 10
[0068] f1(p) OilInt ,k) and f1(p OilInt ,T Err The reason for choosing the smaller of the two is that f1(p) OilInt ,T Err f1(p) is the minimum pressure that can lower the oil temperature. Increasing the oil pressure will not lower the oil temperature. OilInt ,T Err () is the maximum value for increasing the target oil pressure.
[0069] 2) When the engine coolant temperature T CoolantAct With atmospheric temperature T Ambient The difference T CoolantErr When the temperature exceeds the preset temperature T2 (5℃ in this example), the target oil pressure p OilDsrd for:
[0070] p OilDsrd =p OilInt +max{0,max[f2(p OilInt ,k),f2(p OilInt ,T CoolantErr )]}
[0071] In the formula, T CoolantErr The difference between the target engine coolant temperature and the engine coolant temperature; k is the adjustment characteristic value of the target oil pressure. The larger the target oil pressure adjustment characteristic value k is, the greater the target oil pressure correction. This will be discussed in detail later. It mainly improves the target oil pressure from the perspective of improving thermal management performance and avoiding knocking.
[0072] When the temperature difference between the engine coolant and the ambient temperature is too large, the oil pressure is further increased to dissipate the heat of the coolant into the atmosphere, reduce the engine's thermal load, and prevent engine knocking.
[0073] Where f2(p)OilInt ,T CoolantErr The calibration basis is based on different T CoolantErr The continuous time during which the engine coolant temperature accuracy (i.e., the difference between the target coolant temperature and the actual coolant temperature) exceeds ±2.5℃ shall not exceed 0.5s. The calibration in this example is shown in Table 4.
[0074] Table 4f2(p) OilInt ,T CoolantErr Calibration table
[0075]
[0076] Target oil pressure adjustment characteristic values k and f2(p) OilInt The method for determining the target oil pressure adjustment characteristic value k is as follows: The larger the target oil pressure adjustment characteristic value k, the greater the target oil pressure correction. Its calibration is based on the following conditions: under these conditions, the engine does not experience high-intensity knocking (high-intensity knocking refers to knocking that causes a delay in ignition angle exceeding 6° crankshaft angle), and the engine's firing torque accuracy (engine firing torque accuracy refers to the difference between the requested firing torque and the actual firing torque divided by the requested firing torque) is within ±5%, and the wheel-end torque accuracy (wheel-end torque accuracy refers to the difference between the requested torque and the actual torque at the wheel end) is within ±5%. The deviation (divided by the total wheel end requested torque) is within ±5%, and the engine coolant temperature accuracy (i.e., the difference between the target coolant temperature and the actual coolant temperature) exceeds ±2.5℃ for no more than 0.5s continuously. The VVT (Variable Valve Timing) control accuracy is not reduced compared with the VVT control accuracy before oil pressure adjustment (VVT control accuracy refers to the difference between the target VVT phase and the actual VVT phase divided by the target VVT phase). That is, the VVT control accuracy after adjusting the target oil pressure under this condition is equivalent to or improved compared with the VVT control accuracy when the target oil pressure is not adjusted. The calibration of this example is shown in Table 5.
[0077] Table 5f2(p) OilInt ,k) Calibration Table
[0078]
[0079] The determination of T2 depends on the oil temperature T. Oil With engine coolant temperature T CoolantAct The difference T OilErr The greater the difference, the more the oil pressure needs to be increased to lower the oil temperature. Lowering the oil temperature allows the oil to more easily carry some of the heat from the engine back to the oil pan, where it is radiated into the air, helping to cool the engine quickly. The preset temperature below T2 is a calibration value established during vehicle development. This value will be continuously updated through self-learning at different stages of the vehicle's lifecycle after mass production and can be stored after power-off. The calibration in this example is shown in Table 6.
[0080] Table 6T2 Calibration Table
[0081] <![CDATA[T OilErr (℃)]]> 2 3 5 6 8 10 T2(℃) 5 4 3.5 3 2.5 2
[0082] f2(p) OilInt ,k) and f2(p OilInt ,T Err The reason for choosing the larger of the two is to ensure both accurate water temperature control and performance such as torque, VVT, and engine knock protection.
[0083] It should be noted that the engine coolant temperature refers to the actual engine coolant temperature.
[0084] When either of the above two methods satisfies the entry condition, the final target oil pressure p OilDsrdFinal equal to target oil pressure p OilDsrd However, when both of the above methods fail, the final target oil pressure p OilDsrdFinal :
[0085]
[0086] In the formula, N = 1, 2, 3..., p OilDsrdFinal (N-1) represents the final target oil pressure p at time N-1. OilDsrdFinal ;p OilDsrdFinal (N) represents the target oil pressure at time N; the time difference between time N-1 and time N is a fixed update period Δt (10ms in this example); p OilInt (N) represents the initial target oil pressure p at time N. OilInt Specifically, when N=1, i.e., p OilDsrdFinal (0) equals the target oil pressure p in the previous sampling period before exiting the first and second methods. OilDsrd T is the filtering time, which is 2s in this example. The basis for this selection is that the difference between the engine coolant temperature and the target coolant temperature when entering the third case does not exceed ±3℃.
[0087] The adjustment characteristic value k of the target oil pressure is calculated as follows:
[0088]
[0089] Among them, M Sprk Req M represents the requested / target torque value for the fire circuit. AirAct T represents the actual value of the air circuit torque. CoolantErr M represents the difference between the target water temperature and the actual water temperature. Max The maximum torque of the engine (the maximum torque of the engine can be found in patent CN202010632793.4 "Method for Determining the Maximum Output Torque of a Gasoline Engine"), dr SprkEff Engine ignition angle efficiency r SprkEffrate of change, SOC Diff M represents the difference between the target SOC and the current actual SOC (i.e., state of charge, which reflects the battery's remaining capacity) of the high-voltage power battery. WheelTrq Req M requests torque at the wheel ends of the entire vehicle. WheelTrqAct r represents the actual torque at the wheel end of the entire vehicle. Adp To learn the correction coefficient.
[0090] The reason why the above specific parameters are used as adjustment characteristic values for the target oil pressure is mainly because:
[0091] 1) In Excessive torque (indicating high engine torque demand but low actual torque capability) and water temperature difference T CoolantErr When the value is negative (indicating that the water temperature is too high, which is detrimental to engine fuel economy and makes it impossible to achieve the required torque response), it is necessary to appropriately increase the oil pressure to reduce the oil temperature, thereby improving engine combustion economy and achieving the required torque; this is from the perspective of engine performance.
[0092] Based on this, firstly, calibrate Its engine ignition angle efficiency r SprkEff rate of change dr SprkEff Within a fluctuation range of ±0.05 / s, the difference between the target SOC and the current actual SOC of the high-voltage power battery is SOC. Diff The specific calibration parameters for this example are shown in Table 7, which are calibrated based on a tolerance of ±5%.
[0093] Table 7 Calibration table
[0094]
[0095] 2) In Excessive torque (indicating the engine's actual torque capability is already close to its maximum torque), and dr SprkEff When the value is positive (indicating that the ignition angle efficiency is increased to respond to the torque demand), in order to avoid the possibility of engine knocking, it is necessary to appropriately increase the oil pressure to reduce the oil temperature, thereby protecting the engine; this is from the perspective of protecting the engine's lifespan.
[0096] Based on this, after calibration Then, calibration Its difference between the target SOC and the current actual SOC of the high-voltage power battery Diff The specific calibration parameters for this example are shown in Table 8, which are based on a tolerance of ±5%.
[0097] Table 8 Calibration table
[0098]
[0099]
[0100] 3) In Excessive (indicating a large torque demand at the wheel ends), and the SOC difference (SOC) Diff When the pressure is too high (indicating that the current actual SOC is too low and the battery discharge power is poor), in order to improve the battery discharge power to respond to the wheel-end torque request, it is necessary to appropriately increase the oil pressure and reduce the coolant temperature (the engine coolant and motor coolant share the same cooling system), thereby improving the wheel-end torque. This is from the perspective of vehicle dynamics.
[0101] Based on this, after calibration and Then, calibration The specific calibration parameters for this example are shown in Table 9.
[0102] Table 9 Calibration table
[0103]
[0104] Finally, (1+r) was determined. Adp The target oil pressure self-learning correction factor r in ) Adp The self-learning correction factor r during each driving cycle of the vehicle Adp It will only be updated once at most.
[0105] The learning conditions are:
[0106] (1) The engine is running;
[0107] (2) The engine did not experience high-intensity knocking;
[0108] (3) The accuracy of the engine's firing circuit torque is within the preset range, which is ±5% in this example;
[0109] (4) The accuracy of the wheel end torque of the whole vehicle is within the preset range, which is ±5% in this example;
[0110] (5) The vehicle mileage since the last target oil pressure self-learning correction factor update exceeds the preset value, which is 20,000 kilometers in this example.
[0111] If all of the above conditions are met:
[0112] 1) If the engine coolant temperature accuracy remains within the preset range (±2.5℃ in this example), and the VVT control accuracy exceeds the preset range (±2%) for more than the preset time t1 (30s in this example), then the target oil pressure self-learning correction factor r Adp With C1 added, the value in this example is 0.008;
[0113] 2) If the engine coolant temperature accuracy exceeds the preset range (±2.5℃ in this example) and the target coolant temperature is not greater than the actual coolant temperature, and its continuous duration exceeds the preset time t2 (t2 is greater than t1, 60s in this example), and the VVT control accuracy remains within the preset range (±2% in this example), then the target oil pressure self-learning correction factor r Adp With C2 added, the value in this example is 0.005;
[0114] 3) If the engine coolant temperature accuracy exceeds the preset range (±2.5℃ in this example) and the target coolant temperature is greater than the actual coolant temperature, and the time exceeds the preset time t1 (60s in this example), and the VVT control accuracy remains within the preset range (±2% in this example), then the target oil pressure self-learning correction factor r is adjusted. Adp Subtracting C3, the value in this example is 0.002;
[0115] 4) If the engine coolant temperature accuracy exceeds the preset range (±2.5℃ in this example) and the target coolant temperature is not greater than the actual coolant temperature, and the time exceeds the preset time t2 (t2 is greater than t1, 60s in this example), and the VVT control accuracy exceeds the preset range (±2%) for more than the preset time t1 (30s in this example), then the target oil pressure self-learning correction factor r Adp With C4 added, the value in this example is 0.01;
[0116] 5) In other cases, the target oil pressure self-learning correction factor r Adp The learning process remains unchanged.
[0117] Because the performance of various components of a vehicle varies at different stages of its life cycle, the engine continuously learns throughout its entire life cycle; this learning value r... Adp Learning value r Adp The number of consecutive increments CNT1 (once a learning value r is encountered during this learning process) Adp If the value decreases or remains unchanged, then CNT1 is reset to zero, and the learning value r is... Adp The number of consecutive decreases is CNT2 (once a learning value r is reached during this learning process). Adp If the value increases or remains unchanged, then CNT2 will be reset to zero, along with preset temperature T1, preset temperature T2, and learning value r. Adp The ambient temperature and actual engine coolant temperature at the time of update are both stored in the controller's EEPROM after power-off. If:
[0118] 1) Learning value r Adp The atmospheric temperature at the update time is greater than the learning value r. AdpIf the actual engine coolant temperature at the time of update is found, and CNT1 exceeds the preset value (100 in this example), then the preset temperature T1 is updated to 1.01 times the value of the last update, and CNT1 is immediately cleared to zero.
[0119] 2) Learning value r Adp The atmospheric temperature at the update time is greater than the learning value r. Adp If the actual engine coolant temperature at the time of update is found, and CNT2 exceeds the preset value (100 in this example), then the preset temperature T2 is updated to 0.98 times the value of the last update, and CNT2 is immediately cleared to zero.
[0120] 3) Learning value r Adp The atmospheric temperature at the update time is no greater than the learning value r. Adp If the actual engine coolant temperature at the time of update is found, and CNT2 exceeds the preset value (100 in this example), then the preset temperature T2 is updated to 1.015 times the value of the last update, and CNT2 is immediately cleared to zero.
[0121] 4) Learning value r Adp The atmospheric temperature at the update time is no greater than the learning value r. Adp If the actual engine coolant temperature at the time of update is found, and CNT1 exceeds the preset value (100 in this example), then the preset temperature T1 is updated to 0.975 times the value of the last update, and CNT1 is immediately cleared to zero.
[0122] 5) T1 and T2 are not updated in other cases.
[0123] The above completes the description of the method for controlling the target oil pressure of the engine.
[0124] It should be noted that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.
[0125] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.
[0126] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are 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 within the scope of protection of the present invention.
Claims
1. A method for controlling target oil pressure in an engine, characterized in that, Includes the following steps: When the atmospheric temperature With engine coolant temperature difference When the temperature exceeds the first preset temperature T1, the oil pressure is adjusted according to the original target oil pressure. Target oil pressure adjustment characteristic value and atmospheric temperature With engine coolant temperature difference Determine the target oil pressure : In the formula, From the original target oil pressure Adjustment characteristic value of target oil pressure The calibration results were obtained based on the following conditions: the engine did not experience high-intensity knocking under these conditions, the engine's firing line torque accuracy was within the preset firing line torque accuracy range, the wheel end torque accuracy was within the preset wheel end torque accuracy range, the engine coolant temperature accuracy was within the preset coolant temperature range, and the variable valve timing (VVT) control accuracy was not reduced compared to the VVT control accuracy before oil pressure adjustment. It is calibrated by the original target oil pressure and the difference between atmospheric temperature and engine coolant temperature. The calibration basis is the minimum oil pressure at which the oil temperature cannot be reduced under different atmospheric temperature and engine coolant temperature differences. When the engine coolant temperature With atmospheric temperature difference When the temperature exceeds the second preset temperature T2, the oil pressure is adjusted according to the original target oil pressure. Target oil pressure adjustment characteristic value and engine coolant temperature With atmospheric temperature difference Determine the target oil pressure : In the formula, From the original target oil pressure Adjustment characteristic value of target oil pressure The calibration results are obtained based on the following conditions: the engine does not experience high-intensity knocking under these conditions, the engine's firing circuit torque accuracy is within the preset firing circuit torque accuracy range, the wheel end torque accuracy is within the preset wheel end torque accuracy range, the engine coolant temperature accuracy exceeds the preset coolant temperature accuracy range for no more than the preset continuous time, and the variable valve timing (VVT) control accuracy is not reduced compared to the VVT control accuracy before oil pressure adjustment. The calibration is obtained from the original target oil pressure and the difference between engine coolant temperature and atmospheric temperature. The calibration basis is that the continuous time for the engine coolant temperature accuracy to exceed the preset coolant temperature accuracy under different engine coolant temperature and atmospheric temperature differences does not exceed the preset continuous time. If either of the above two conditions is met, then the final target oil pressure will be achieved. equal to target oil pressure Otherwise, based on the final target oil pressure at the previous moment and the fixed update cycle Filtering time and the original target oil pressure at that moment. Determine the final target oil pressure at this moment. : In the formula, for The ultimate target oil pressure at any given moment for The final target oil pressure at time N=1, Equal to the target oil pressure at the previous moment ;time With time The time difference is a fixed update cycle , for The original target oil pressure at any given time. .
2. The method for controlling the target oil pressure of an engine according to claim 1, characterized in that, When the atmospheric temperature With engine coolant temperature difference When the temperature exceeds the first preset temperature T1, the preset fire circuit torque accuracy range is within ±5%, the preset wheel end torque accuracy range is within ±5%, and the preset water temperature accuracy range is within ±2.5℃.
3. The method for controlling the target oil pressure of an engine according to claim 1, characterized in that, When the engine coolant temperature With atmospheric temperature difference When the second preset temperature T2 is exceeded, the preset fire circuit torque accuracy range is within ±5%, the preset wheel end torque accuracy range is within ±5%, the preset water temperature accuracy range is within ±2.5℃, and the preset continuous time is 0.5s.
4. The method for controlling the target oil pressure of an engine according to any one of claims 1 to 3, characterized in that, Adjustment characteristic value of target oil pressure The calculation method is as follows: In the formula, This represents the requested / target torque value for the fire circuit. This is the actual value of the air circuit torque. The difference between the target water temperature and the actual water temperature. This is the engine's maximum torque. For engine ignition angle efficiency rate of change, This represents the difference between the target SOC and the current actual SOC of the high-voltage power battery. Request torque for the entire wheel end, This represents the actual torque at the wheel end. This is a self-learning correction factor; First calibration It is in the engine ignition angle efficiency rate of change Within the preset fluctuation range and the difference between the target SOC and the current actual SOC of the high-voltage power battery The calibration was performed based on a preset SOC range. Then calibrate It is the difference between the target SOC and the current actual SOC of the high-voltage power battery. The calibration was performed based on a preset SOC range. Final calibration , The larger, The larger, the better The larger.
5. The method for controlling the target oil pressure of an engine according to claim 4, characterized in that, Self-learning correction factor The update is as follows: Self-learning correction factor during each driving cycle of the vehicle It will only be updated once at most, and the self-learning conditions are: (1) The engine is running; (2) No high-intensity knocking occurred in the engine; (3) The accuracy of the engine's firing circuit torque is within the preset firing circuit torque accuracy range; (4) The accuracy of the wheel end torque of the whole vehicle is within the preset wheel end torque accuracy range; (5) The vehicle mileage since the last target oil pressure self-learning correction factor update exceeds the preset mileage value; If all of the above conditions are met: 1) If the engine coolant temperature accuracy is maintained within the preset coolant temperature accuracy range, and the continuous time for which the variable valve timing (VVT) control accuracy exceeds the preset control accuracy range exceeds the preset time t1, then the target oil pressure self-learning correction factor is increased by C1. 2) If the engine coolant temperature accuracy exceeds the preset coolant temperature accuracy range and the target coolant temperature is not greater than the actual coolant temperature, and its continuous time exceeds the preset time t2, and the variable valve timing (VVT) control accuracy is always maintained within the preset control accuracy range, then the target oil pressure self-learning correction factor is increased by C2. 3) If the engine coolant temperature accuracy exceeds the preset coolant temperature accuracy range and the target coolant temperature is greater than the actual coolant temperature, and its continuous time exceeds the preset time t1, and the variable valve timing (VVT) control accuracy is maintained within the preset control accuracy range, then the target oil pressure self-learning correction factor is reduced by C3. 4) If the engine coolant temperature accuracy exceeds the preset coolant temperature accuracy range and the target coolant temperature is not greater than the actual coolant temperature, and its continuous time exceeds the preset time t2, and the time for which the variable valve timing (VVT) control accuracy exceeds the preset control accuracy range exceeds the preset time t1, then the target oil pressure self-learning correction factor is increased by C4; where C1, C2, C3 and C4 are all preset values, C2 is less than C1, and C1 is less than C4; 5) Under other circumstances, the target oil pressure self-learning correction factor remains unchanged during this learning process.
6. The method for controlling the target oil pressure of an engine according to claim 5, characterized in that, The initial determination of the first preset temperature T1 depends on the engine oil temperature. With engine coolant temperature The difference Difference The larger the value, the larger the first preset temperature T1, and then it will be updated through self-learning. The initial determination of the second preset temperature T2 depends on the engine oil temperature. With engine coolant temperature The difference Difference The larger the value, the smaller the second preset temperature T2, and then it will be updated through self-learning.
7. The method for controlling the target oil pressure of an engine according to claim 6, characterized in that, The self-learning updates for the first preset temperature T1 and the second preset temperature T2 include: Obtain self-learning correction factor The number of consecutive increases (CNT1), self-learning correction factor The number of consecutive decreases (CNT2), the first preset temperature (T1), the second preset temperature (T2), and the self-learning correction factor. Update the ambient temperature and actual engine coolant temperature at the current moment; if: 1) Self-learning correction factor Atmospheric temperature at the update time is greater than the self-learning correction factor. If the actual engine coolant temperature at the time of update is found, and CNT1 exceeds the preset value, then the first preset temperature T1 is updated to 1.01 times the value of the last update, and CNT1 is immediately cleared to zero. 2) Self-learning correction factor Atmospheric temperature at the update time is greater than the self-learning correction factor. If the actual engine coolant temperature at the time of update is found, and CNT2 exceeds the preset value, then the first preset temperature T2 will be updated to 0.98 times the value of the last update, and CNT2 will be immediately cleared to zero. 3) Self-learning correction factor The atmospheric temperature at the update time is no greater than the self-learning correction factor. If the actual engine coolant temperature at the time of update is found and CNT2 exceeds the preset value, then the first preset temperature T2 will be updated to 1.015 times the value of the last update, and CNT2 will be immediately cleared to zero. 4) Self-learning correction factor The atmospheric temperature at the update time is no greater than the self-learning correction factor. If the actual engine coolant temperature at the time of update is found and CNT1 exceeds the preset value, then the first preset temperature T1 will be updated to 0.975 times the value of the last update, and CNT1 will be immediately cleared to zero. 5) Under other circumstances, the first preset temperature T1 and the second preset temperature T2 are not updated.