Engine and electric drive cooperative efficiency scheduling method based on target working condition interval

Abstract

The invention relates to the technical field of cooperative scheduling, in particular to an engine and electric drive cooperative efficiency scheduling method based on a target working condition interval, and the method comprises the following steps: matching a predefined target energy transfer chain interval according to a real-time required power change rate and a road slope; in the target energy transfer chain interval, a total transfer efficiency model from an output shaft to a wheel end is constructed, and the total transfer efficiency model is associated with engine efficiency, electric drive efficiency and a transmission chain loss rate; and according to the total transmission efficiency model, the engine torque, the motor torque and the gearbox speed ratio are synchronously adjusted, so that the energy transmission path loss is minimized. According to the method, three-stage combined target energy transfer chain interval judgment logic of'basic interval + boundary scaling + loss constraint 'is constructed. Different from a rough method only based on gradient single parameter static division in the prior art, the scheme can dynamically adjust the available power range of a transmission chain, and three typical operation states of level road, climbing and heavy load are effectively covered.

Description

Technical Field

[0001] The present invention relates to the field of collaborative scheduling technology, and in particular to a method for collaborative efficiency scheduling of an engine and an electric drive based on a target operating range. Background Art

[0002] Hybrid and electric drive systems are increasingly being used in vehicle energy management. The power synergy between the engine and motor has become a key factor influencing vehicle energy consumption, responsiveness, and transmission stability. Traditional energy allocation strategies are often based on fixed operating condition mapping or rule-based control. They often use single indicators such as engine load factor, battery SOC, and motor efficiency to determine switching, lacking unified modeling and real-time evaluation of dynamic operating condition response characteristics and driveline loss characteristics.

[0003] On the one hand, existing methods typically judge the driving environment based on the driver's throttle position or slope, and select engine, motor, or combined drive mode accordingly. However, this classification often relies on static empirical thresholds and fails to consider the impact of rapidly changing operating conditions on energy path stability. This is particularly true during acceleration, deceleration, or sudden changes on slopes, which can easily lead to delayed strategy switching, increased torque fluctuations, and even reduced energy efficiency.

[0004] Furthermore, efficiency models generally employ simplified forms, such as linear efficiency superposition or weighted averaging. These models fail to distinguish the independent contributions of electrical, mechanical, and engine parasitic losses, and fail to establish a mathematical response relationship between total transmission efficiency and control variables. This results in a control strategy that lacks derivative-driven optimization capabilities. Furthermore, the thermal state of the transmission system, such as transmission oil temperature and structural loss variations, is not factored into scheduling constraints, creating overload risks. Summary of the Invention

[0005] The present invention provides a method for scheduling the coordinated efficiency of the engine and electric drive based on the target operating range. It integrates a new scheduling method that dynamically identifies the target operating range, models the multi-path loss of the transmission chain, and optimizes the derivative drive strategy to achieve efficient coordination among the engine, electric drive system, and gearbox, thereby improving the energy efficiency and system stability of the entire vehicle.

[0006] A method for scheduling engine and electric drive synergistic efficiency based on a target operating range includes the following steps: S1. Match the predefined target energy transfer chain interval based on the real-time power change rate and road slope; S2. Constructing a total transmission efficiency model from the output shaft to the wheel end within the target energy transmission chain range, wherein the total transmission efficiency model is associated with engine efficiency, electric drive efficiency, and transmission chain loss rate; S3. Synchronously adjust the engine torque, motor torque, and transmission ratio based on the overall transfer efficiency model to minimize energy transfer path losses.

[0007] Optionally, the target energy transfer chain interval includes a flat road transfer chain interval, a ramp transfer chain interval and a heavy load transfer chain interval, and one of the flat road transfer chain interval, the ramp transfer chain interval or the heavy load transfer chain interval is selected as the target energy transfer chain interval based on the pre-division basis of the absolute value of the slope.

[0008] Optionally, the S1 further includes interval boundary correction, which scales the boundaries of the initial interval of the selected target energy transfer chain interval based on the real-time required power change rate.

[0009] Optionally, S1 further includes loss constraint checking, specifically including calculating an estimated transmission chain loss rate of the interval after the interval boundary correction, and returning to the initially selected interval if the estimated transmission chain loss rate exceeds a loss rate threshold.

[0010] Optionally, the S2 specifically includes: S21, within the locked target energy transfer chain range, obtain the engine base efficiency value based on the engine speed-torque MAP , based on the motor speed-torque MAP to obtain the basic efficiency value of the electric drive system ; S22, according to the current working status of the transmission chain, calculates multiple categories of loss rates in real time, including mechanical loss rate , electrical loss rate and parasitic loss rate ; S23, build the total transfer efficiency model: ;in, It is the total transmission efficiency of engine + electric drive + transmission chain.

[0011] Optionally, the multi-category loss rate includes: Mechanical loss rate : Includes gear meshing efficiency loss and bearing friction loss, obtained by looking up the table of transmission input shaft torque and oil temperature; Electrical loss rate : Including the Joule loss of the power cable and the switching loss of the inverter, linearly fitted by the square value of the driving current; Parasitic loss rate : Includes pumping loss and accessory power consumption, calibrated by engine intake pressure and battery voltage.

[0012] Optionally, the S2 further includes operating condition constraint loading, specifically including injecting the boundary conditions of the target energy transfer chain interval as inequality constraints into the total transfer efficiency model.

[0013] Optionally, the S3 includes loss sensitivity analysis, specifically including analyzing the influence of engine torque, motor torque and gearbox ratio on the total efficiency based on the constructed total transfer efficiency model, and obtaining three sets of loss sensitivity coefficients by calculating the efficiency response change trends respectively, which are used to characterize the dependence intensity of efficiency on each control variable.

[0014] Optionally, the S3 also includes establishing a multi-parameter joint optimization model for maximizing multi-parameter efficiency based on the required power of the vehicle as a constraint condition, combining the engine torque, motor torque and transmission ratio. The multi-parameter joint optimization model ensures that the total output traction meets the required power of the vehicle while maximizing the overall energy transfer efficiency from the source to the wheels, thereby achieving control decisions with optimal energy consumption.

[0015] Optionally, the S3 further includes a dynamic execution strategy; Different control strategies are selected based on the calculation results of the three sets of loss sensitivity coefficients and real-time operating condition information: When the efficiency sensitivity of the transmission ratio is higher than that of the engine and motor, the transmission ratio should be adjusted first to reduce the transmission system loss; When the signs of the sensitivity of the engine and the motor are opposite, indicating that the direction of their contribution to efficiency is different, the torque transfer strategy is executed, that is, the engine load is reduced and compensated by the motor; When it is detected that the current mechanical loss rate exceeds the preset loss threshold, the gearbox ratio adjustment operation is temporarily frozen to prevent further deterioration of the gears and bearings under high loss conditions.

[0016] Beneficial effects of the present invention: This invention, by introducing a dual-parameter coupling mechanism based on road slope and the rate of change of required power, constructs a three-level combination of "basic interval + boundary scaling + loss constraint" for determining the target energy transfer chain interval. Unlike the crude prior art method of static partitioning based solely on the slope parameter, this solution dynamically adjusts the available power range of the transmission chain, effectively covering three typical operating conditions: flat road, climbing, and heavy load. Furthermore, the scaling ratio is regulated based on an exponential model constructed from the power change rate and oil temperature, ensuring the dynamic responsiveness and thermal stability of the expanded interval. This ensures that the scheduling strategy remains within the physically feasible, low-loss target interval, improving the strategy's robustness and energy efficiency adaptability.

[0017] In efficiency modeling, this invention links the efficiency and loss rates of the three energy paths—the engine, motor, and transmission—in a chain-like manner. It then independently decouples and models the three key loss factors—mechanical, electrical, and parasitic—for precise quantification through a lookup table of input shaft torque and oil temperature, current square fitting, and intake pressure-voltage calibration. Compared to traditional linear weighted or black-box modeling approaches, this method more realistically reflects the energy dissipation process under varying loads and operating conditions. By injecting target interval boundaries into the constrained model, it eliminates model extrapolation errors, significantly improving energy consumption assessment accuracy and strategy controllability, and providing a higher-resolution control foundation for optimization.

[0018] The present invention introduces the efficiency partial derivative sensitivity index of engine torque, motor torque and gearbox ratio at the optimization execution layer to construct a real-time control priority determination mechanism under multivariable response trends. Compared with traditional methods that rely on empirical tables or power weighting, this solution can achieve dynamic strategy selection at a fine granularity, such as giving priority to gear shifting in scenarios dominated by gearbox efficiency, automatically transferring the torque output load when the engine and motor efficiency contributions are in opposite directions, and freezing the speed ratio adjustment under critical conditions of mechanical loss rate to protect structural safety. By combining derivative analysis with dynamic condition drive, the system can intelligently select the output path that is most conducive to overall efficiency while meeting the power requirements of the entire vehicle, thereby achieving a highly coordinated balance between response speed, energy consumption control and thermal safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 Schematic diagram of the method steps of an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art may also implement some known technologies in other alternative ways. The accompanying drawings are only for describing the embodiments in more detail and are not intended to limit the present invention in any specific way.

[0022] like Figure 1 As shown, a method for scheduling engine and electric drive synergistic efficiency based on a target operating range includes the following steps: S1. Match the predefined target energy transfer chain interval based on the real-time power demand change rate and road slope.

[0023] S1 specifically includes the following steps: S11, basic section selection: select the basic section type according to the absolute value of the road slope, where: When the absolute value of the slope When , select the flat road transfer chain interval; when When , select the ramp transfer chain interval; when , select Overload Transfer Chain Interval.

[0024] Three basic interval divisions based on the absolute value of the road slope (flat road, ramp, heavy load): Slope is a key factor affecting vehicle mechanical loads, particularly longitudinal traction and gravity. As slope increases, the required traction increases nonlinearly, significantly increasing the load on the drivetrain. Therefore, it is necessary to partition the vehicle based on slope to optimize the efficiency of the dispatch strategy under varying loads.

[0025] In the field of vehicle dynamics and vehicle control, gradients of 5% and 10% are commonly used as empirical thresholds for determining "light load," "medium load," and "heavy load" scenarios. Gradients under 5% are considered normal operating conditions, while gradients above 10% are considered heavy-load climbing scenarios requiring high power output. This classification is often used in strategies such as transmission shifting logic and engine operating condition adjustments.

[0026] On flat roads, the transmission chain primarily handles steady driving, with losses primarily due to internal friction and gear meshing efficiency. On slopes and under heavy loads, in addition to conventional losses, factors such as gear lateral forces and reduced lubrication efficiency due to temperature rise must also be considered. Therefore, using different ranges helps to more precisely describe energy transfer efficiency.

[0027] S12, dynamic boundary correction: based on real-time demand power change rate Scale the boundaries of each basic interval: like , then expand the lower limit of the interval ; like , then compress the upper limit of the interval .

[0028] The nature of the scaling is based on the following parameterized model: ; This formula represents the dynamic expansion or compression of the working range boundary of the transfer chain; where, Indicates the dynamic expansion / compression amount of the transfer chain interval boundary, represents the rate of change of required power, Indicates the current transmission oil temperature. represents the interval response coefficient (calibration parameter used to adjust the model sensitivity), Indicates the oil temperature attenuation coefficient (controls the effect of oil temperature on boundary correction). Values ​​k = 0.12 to 0.18: Response sensitivity of adjustment range scaling; Values ​​α = 0.015 to 0.02: Oil temperature attenuation factor (approximately 1.5% to 2% for every 1°C increase in oil temperature); The real-time power demand change rate refers to the rate of change of the driving force power required by the vehicle per unit time. The current power demand is obtained from the vehicle controller (VCU). , continuously collect the required power at two moments 、 , approximated by the following formula: ;in, is the sampling interval.

[0029] A positive power rate of change indicates the vehicle is accelerating, requiring the system to quickly transition from a static or low-load state to a high-load state. Continuing to use the original base range at this point may result in reduced transmission efficiency due to insufficient upper power limits. Therefore, the lower range limit should be expanded in advance to release more available low-speed, high-torque operating points for the engine or motor to select. During high-speed acceleration, the transient response caused by inertial loads is significant, and the traditional lower range limit is insufficient to accommodate the peak torque transmission chain. Therefore, by expanding the lower range limit by 10% to 15%, the system is guided into a stronger power transmission region, meeting dynamic transition requirements and ensuring transmission efficiency. Based on field testing across multiple vehicle models, it has been found that not expanding the lower range at speeds greater than 4 kW / s increases the risk of engine lag and frequent transmission upshifts. The 10% to 15% expansion value represents an empirically optimized range that balances response speed with driveline losses.

[0030] A negative power rate of change indicates that the vehicle is in a coasting, deceleration, or braking condition, during which the demand for drive power decreases rapidly. If the original upper limit of the range is retained, the engine or motor may operate in an unnecessary high-power range, reducing energy efficiency. When the power is suddenly reduced under high load, if the upper limit is not reduced, the engine may still output excess power, causing heat loss. Therefore, compressing the upper limit of the range can suppress system lag and excess power. A compression of 5% to 8% can effectively control energy waste without causing excessive changes in system operating conditions that affect smoothness. It is a reasonable range that takes into account both response and stability in actual measurement and debugging.

[0031] Example 1: Extending the lower limit (acceleration): Current oil temperature ; ; Pick 、 ; Substituting into the formula: ; If the lower limit of the original range is 2.5kW, then: expansion ratio , falling within the recommended range: 10%-15%.

[0032] Example verification 2: Compression upper limit (deceleration): Current oil temperature ; ; Also take 、 ; Substitute: ; If the upper limit of the original range is 2.5kW: compression ratio ; Falls within the recommended range: 5%-8%.

[0033] S13, loss constraint verification: estimate the transmission chain loss rate for the corrected target energy transmission chain interval calculate: like , then it falls back to the corresponding basic interval.

[0034] Among them, the loss rate threshold It is related to the transmission oil temperature and can be determined by the following compensation mechanism: ;in, represents the estimated loss rate of the transmission chain, Temperature-corrected loss rate threshold, Indicates the reference threshold (calibrated value 12%), Indicates the reference temperature (usually the calibration temperature 60°C), Indicates the oil temperature sensitivity coefficient (0.003 / °C).

[0035] S2. Within the target energy transfer chain range, construct a total transfer efficiency model from the output shaft to the wheel end, wherein the total transfer efficiency model is related to the engine efficiency, the electric drive efficiency, and the transmission chain loss rate.

[0036] S2 specifically includes the following steps: S21, basic efficiency mapping: within the locked target energy transfer chain range: Obtain the engine basic efficiency value through the engine speed-torque MAP ; Obtain the basic efficiency value of the electric drive system through the motor speed-torque MAP diagram .

[0037] The speed-torque MAP diagram is the engine / motor at different speeds and output torque The working efficiency matrix under the above conditions is obtained through real vehicle calibration or bench testing. The basic efficiency value refers to the energy conversion efficiency of the system itself under ideal conditions (without additional load and loss). The specific acquisition process is as follows: 1: Determine the current operating point and obtain the following real-time operating parameters from the vehicle control system (VCU): current engine / motor speed 、 , current torque of the engine / motor 、 , this operating point must be within the currently locked target energy transfer chain range.

[0038] 2: Call the calibration efficiency map and preset the two-dimensional MAP table structure in the ECU or VCU: : Engine speed-torque efficiency diagram; : Electric drive system efficiency diagram (including the comprehensive efficiency of the motor and electronic control unit); Each pair The input value corresponds to an efficiency output, which reflects the energy conversion rate at that point.

[0039] 3: Interpolation calculation to obtain efficiency, due to the current operating point It does not necessarily fall exactly on the table nodes, so bilinear interpolation or high-order interpolation is required: Hint: Bilinear interpolation if the current 、 , located between the four points in the table below.

[0040] Table 1 Interpolation diagram

[0041] The interpolation formula is as follows: ; Applied to the efficiency diagrams of the engine and motor respectively, we get: ; ; 4: Check whether the current operating point is within the target energy transfer chain range; if it exceeds the interval boundary, the interpolation result is discarded, and the user is prompted to use the default efficiency or perform limit protection.

[0042] S22, loss path quantification: Based on the current transmission chain working status, calculate the following three independent loss rates: S221, mechanical loss rate : Includes gear meshing efficiency loss and bearing friction loss, obtained by looking up the table based on the transmission input shaft torque and transmission oil temperature; mechanical loss rate The acquisition is as follows: Data source: Transmission input shaft torque : Estimated by powertrain torque sensor or engine output; Transmission oil temperature : Real-time collection through oil temperature sensor.

[0043] Pre-establish a two-dimensional calibration table (obtained through bench testing): ; Horizontal axis of the table: input torque (distribution range, such as 0~400 Nm); Vertical axis of the table: oil temperature (distribution range is -20~120 °C); Unit value: Transmission mechanical loss rate under the corresponding combination (the unit is a relative value, such as 0.03 means 3%).

[0044] The higher the torque, the greater the gear meshing and bearing side loads, and the higher the losses; Too low oil temperature will cause the viscosity of lubricating oil to increase → friction loss to increase; Excessively high oil temperature will reduce lubrication performance → increase metal contact loss; The table lookup results reflect this type of nonlinear behavior.

[0045] S222, electrical loss rate :Including the Joule loss of the power cable and the switching loss of the inverter, obtained by linear fitting through the square value of the driving current ;Electrical loss rate The acquisition is as follows: Data source: Motor phase current It is collected in real time by the motor controller (MCU) and is the three-phase average RMS value; Current data is used to reflect the load level and Joule effect.

[0046] Fitting model formula ; Calibration coefficients are determined based on experimental data under typical loads , fitting the total power loss of cables, windings and inverters, Indicates the RMS value of the motor drive current, which is the average RMS value of the three-phase current. Represents the fitting coefficient of the square term of the current, representing the Joule loss The weight of the impact on the overall power loss, is a constant term, representing the baseline loss that is independent of current, such as inverter static switching loss and standby loss.

[0047] Fitting data construction method: collecting current under different working conditions Compare the total input / output power to calculate the instantaneous loss rate under each working condition: ;by is the regression fitting of the sample points, is the electrical loss rate of the i-th sampling point, is the electrical input power at the i-th operating point, is the motor output power at the i-th operating point; Construct a regression sample point set for fitting parameters .

[0048] Joule loss The dominant factor is proportional to the square of the current. Item b reflects the baseline consumption of the inverter, such as switching loss and standby loss, and is dynamically adjusted online to adapt to different ambient temperatures.

[0049] S223, parasitic loss rate : Includes engine pumping loss and electric drive accessory power consumption, obtained by checking the calibration chart by combining engine intake pressure and battery voltage. The acquisition is as follows: Data source: Engine intake pressure :Taken from the intake manifold pressure sensor (MAP); Battery voltage : Taken from the electric drive system BMS or main relay controller; Preset 2D joint calibration map: ; Reflects the engine's pumping load (throttle opening is large Strong pumping effect), Indicates the load capacity of the electric drive accessories (such as cooling pumps, air conditioning compressors), and the joint calibration diagram is obtained by calibrating the vehicle under the test bench. The greater the pumping loss, the higher the battery voltage The higher the accessory power, the more clearly the additional loss components can be quantified by separating the engine and accessory load sources.

[0050] S23, dynamic coupling modeling: Construct the overall transfer efficiency model as follows: ; in, It is the total transmission efficiency of engine + electric drive + transmission chain.

[0051] The model divides the energy transfer path from the source (engine, electric drive) to the terminal (wheel) of the power system into three parts: Engine path: Base efficiency is , but also subject to parasitic losses such as pump air loss and accessory power consumption , so As an efficiency correction factor.

[0052] Electric drive path: The conversion efficiency of the motor itself is However, it is limited by the heat loss of components such as inverters and wires, current fluctuation loss, etc., so Correction.

[0053] Drive chain path: Mechanical systems such as gearboxes, differentials, bearings, etc. have friction and meshing losses. Characterize its effective energy retention ratio.

[0054] These three paths are interrelated. A decrease in efficiency in any one path will amplify the overall loss. Therefore, a multiplicative structure is used to express the chain energy loss characteristics.

[0055] The vehicle power transmission process essentially consists of multiple modules connected in series. Losses at each stage affect subsequent energy supply, so efficiency should exhibit multiplicative attenuation rather than additive degradation. Decoupling parasitic, electrical, and mechanical losses through modeling facilitates subsequent optimization of each link, improving diagnostic accuracy and dispatch control capabilities. Incorporating dynamic operating parameters (torque, current, and oil temperature) into the calculation of each loss factor helps the model adjust in real time to environmental and load changes, maintaining prediction accuracy.

[0056] S24, working condition constraint loading: The boundaries of the aforementioned target energy transfer chain interval (such as power, speed, load, etc.) are injected into the above formula as inequality constraints to limit the model to be valid only within the target interval, thereby constructing a limited model with interval constraints.

[0057] The boundary variables of the target energy transfer chain interval include the following dimensions: Power range , max: the required power range allowed within the interval; Speed ​​range : The operating speed range of the engine / motor within the interval; Torque range : Output torque range within the interval Oil temperature range : Boundary conditions used to correct the validity of the loss model.

[0058] Taking the above boundary variables as the operating condition constraints of the model, the following inequality constraints are constructed: ; These constraints act as a function of time The state variables on , ensure that the model is only enabled when the operating condition variables fall into the target range.

[0059] Using a gating function Control whether the model is enabled or not: ; Then the restricted model is constructed as: ; That is, it is used only when all operating variables meet the target energy transfer chain range requirements. Make subsequent scheduling decisions; otherwise the output is 0.

[0060] S3. Synchronously adjust the engine torque, motor torque, and transmission ratio based on the overall transfer efficiency model to minimize energy transfer path losses.

[0061] S3 specifically includes the following steps: S31, loss sensitivity analysis, in the total transfer efficiency model In the figure, the engine torque is , motor torque and gearbox ratio Find the partial derivatives and construct three sets of loss sensitivity coefficients: ; in: is the sensitivity coefficient of engine torque to total efficiency; it indicates the degree of influence of engine torque change on total transmission efficiency; when When increasing engine torque, the overall efficiency will be improved; when When the engine is in a low-efficiency zone, further increasing the torque will reduce the overall efficiency. Can be used to determine if the engine should be "unloaded" and the load transferred to the motor.

[0062] is the sensitivity coefficient of motor torque to total efficiency; it indicates the influence of motor torque change on total transmission efficiency: : Increasing the motor torque is beneficial to improving efficiency, and the motor is in the high-efficiency operating area; : Indicates that the motor is overloaded or in a low-efficiency area and the motor load should be reduced; Combined with Ke, an “engine-motor synergy” scheduling strategy can be formed.

[0063] is the sensitivity coefficient of the gearbox speed ratio to the total efficiency; it indicates the degree of influence of the gearbox speed ratio adjustment on the total efficiency; : The current speed ratio is low. Increasing the speed ratio will help reduce transmission losses. : The current speed ratio is too high, which may cause excessive lateral force or sliding wear of the gears, so it should be reduced; If it is significantly greater than, it means that the gearbox ratio is the dominant variable for efficiency optimization, and the system should give priority to adjusting the ratio. Significantly greater than 、 , which shows that the gearbox ratio is the dominant variable for efficiency optimization, and the system should give priority to adjusting the speed ratio.

[0064] The total transfer efficiency calculated based on the above model is: 、 、 They are engine torque, motor torque, and current gearbox ratio.

[0065] S32, Node Collaborative Optimization: Setting Required Power As the main constraint condition, a multi-parameter joint optimization model is established: , satisfying the following constraints: ; in, is the current required power of the vehicle, is the fixed transmission ratio of the transmission system, is the current vehicle speed, is the equivalent torque output by the engine through the gearbox, constraining the right end Represents the total torque equivalent to that required for vehicle towing.

[0066] The above optimization goal is , indicating that in the current vehicle operating state, the engine torque is sought , motor torque , gearbox ratio The optimal combination of the two maximizes the vehicle's overall energy transfer efficiency. This efficiency encompasses all energy consumption characteristics of the engine, motor, and transmission system and is a key indicator for measuring the vehicle's energy performance.

[0067] The constraints are ; This constraint represents the traction torque jointly output by the engine and motor through the transmission system, which must meet the current required power target of the vehicle. This constraint requires that the combined force output by the two is equal to the traction torque required for the current operation of the vehicle.

[0068] S33, execution strategy: Based on the sensitivity coefficient and real-time working conditions, the following dynamic decision logic is executed: Strategy 1, gearbox ratio priority adjustment: when Prioritizing transmission ratio adjustment indicates that, under current operating conditions, small changes in transmission ratio have a greater impact on overall system efficiency than changes in engine or motor torque. In other words, adjusting the ratio will yield a more efficient improvement. This is used to adjust gear mesh points to optimize energy transfer when the current ratio has the greatest impact on efficiency.

[0069] Under different speed ratios, the gear meshing efficiency and bearing load change significantly. The wrong speed ratio may lead to increased lateral force or torque mismatch. Especially in cases of medium and low speed climbing, high load starting, etc., speed ratio optimization can greatly reduce mechanical losses.

[0070] Decision logic: When it is identified that the transmission ratio is most sensitive to efficiency, priority should be given to adjusting the ratio rather than changing the power output structure, implementing actions such as upshifting or downshifting to allow the engine and motor to operate in a more efficient speed-torque range.

[0071] Strategy 2, engine-motor torque transfer: when Perform engine torque unloading and motor torque compensation; This condition shows that increasing engine torque has a negative impact on efficiency , the motor's increased torque has a positive impact on efficiency , that is, the two have opposite effects on system efficiency, and a power transfer channel can be established to allow the high-efficiency source to take on more output while meeting the power constraint conditions.

[0072] The engine is often in an inefficient state when starting at low temperatures, operating at high altitudes or in non-economic zones, while the motor is usually highly efficient in medium and low load areas and is suitable for providing transitional power support. This strategy is similar to the "energy efficiency diversion" mechanism and is an important control logic for the hybrid system.

[0073] Decision logic: Without changing the total output power, more load is transferred to the more efficient party (motor); the engine is "unloaded" (output torque is reduced), and the motor "compensates" for the gap.

[0074] Strategy 3, transmission ratio freeze protection: when Freeze the gearbox ratio adjustment; used to protect the mechanical system from further disturbances in high-loss / high-temperature conditions, avoiding bearing thermal failure or gear overload. .

[0075] Decision logic: Once the mechanical loss rate is detected If the threshold is exceeded, the gearbox ratio change operation will be frozen immediately, and the execution of gear shifting, gear skipping, speed cutting and other instructions will be prohibited, and the current state will be maintained.

[0076] The present invention encompasses any alternatives, modifications, equivalents, and solutions that fall within the spirit and scope of the present invention. To provide a thorough understanding of the present invention, specific details are described in detail below in connection with the preferred embodiments of the present invention, but those skilled in the art will be able to fully understand the present invention without these detailed descriptions. Furthermore, to avoid unnecessary confusion regarding the essence of the present invention, well-known methods, processes, procedures, components, and circuits have not been described in detail.

[0077] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for scheduling engine and electric drive synergistic efficiency based on a target operating range, characterized in that: The following steps are involved: S1. Match the predefined target energy transfer chain interval based on the real-time power change rate and road slope; S2. Constructing a total transmission efficiency model from the output shaft to the wheel end within the target energy transmission chain range, wherein the total transmission efficiency model is associated with engine efficiency, electric drive efficiency, and transmission chain loss rate; S3. Synchronously adjust the engine torque, motor torque, and transmission ratio based on the overall transfer efficiency model to minimize energy transfer path losses.

2. The method for scheduling engine and electric drive synergistic efficiency based on a target operating range according to claim 1, characterized in that: The target energy transfer chain interval includes a flat road transfer chain interval, a ramp transfer chain interval and a heavy load transfer chain interval. Based on the pre-division basis of the absolute value of the slope, one of the flat road transfer chain interval, the ramp transfer chain interval or the heavy load transfer chain interval is selected as the target energy transfer chain interval.

3. The method for scheduling engine and electric drive synergistic efficiency based on a target operating range according to claim 2, characterized in that: The S1 further includes interval boundary correction, which is to scale the boundaries of the initial interval of the selected target energy transfer chain interval based on the real-time required power change rate.

4. The method for scheduling engine and electric drive synergistic efficiency based on a target operating range according to claim 3, characterized in that: The S1 also includes loss constraint checking, specifically including calculating the estimated transmission chain loss rate of the interval after the interval boundary correction, and if the estimated transmission chain loss rate exceeds the loss rate threshold, returning to the initial selected interval.

5. The method for scheduling engine and electric drive synergistic efficiency based on a target operating range according to claim 1, characterized in that: The S2 specifically includes: S21, within the locked target energy transfer chain range, obtain the engine basic efficiency value based on the engine speed-torque MAP , based on the motor speed-torque MAP to obtain the basic efficiency value of the electric drive system ; S22, based on the current working status of the transmission chain, calculates multiple categories of loss rates in real time, including mechanical loss rate , electrical loss rate and parasitic loss rate ; S23, build the total transfer efficiency model: ;in, It is the total transmission efficiency of engine + electric drive + transmission chain.

6. The method for scheduling engine and electric drive synergistic efficiency based on a target operating range according to claim 5, characterized in that: The multi-category loss rates include: Mechanical loss rate : Includes gear meshing efficiency loss and bearing friction loss, obtained by looking up the table of transmission input shaft torque and oil temperature; Electrical loss rate : Including the Joule loss of the power cable and the switching loss of the inverter, linearly fitted by the square value of the driving current; Parasitic loss rate : Includes pumping loss and accessory power consumption, calibrated by engine intake pressure and battery voltage.

7. The method for scheduling engine and electric drive synergistic efficiency based on a target operating range according to claim 6, characterized in that: The S2 also includes working condition constraint loading, specifically including injecting the boundary conditions of the target energy transfer chain interval as inequality constraints into the total transfer efficiency model.

8. The method for scheduling engine and electric drive synergistic efficiency based on a target operating range according to claim 1, characterized in that: The S3 includes loss sensitivity analysis, which specifically includes analyzing the influence of engine torque, motor torque and transmission ratio on the total efficiency based on the constructed total transmission efficiency model. By calculating the efficiency response change trend respectively, three sets of loss sensitivity coefficients are obtained to characterize the dependence of efficiency on each control variable.

9. The method for scheduling engine and electric drive synergistic efficiency based on a target operating range according to claim 8, characterized in that: The S3 also includes establishing a multi-parameter joint optimization model for maximizing multi-parameter efficiency based on the vehicle's required power as a constraint condition, combining engine torque, motor torque, and transmission ratio. The multi-parameter joint optimization model ensures that the total output traction meets the vehicle's required power while maximizing the overall energy transfer efficiency from the source to the wheels, thereby achieving control decisions that optimize energy consumption.

10. The method for scheduling engine and electric drive synergistic efficiency based on a target operating range according to claim 8, characterized in that: Said S3 also includes a dynamic execution strategy; Different control strategies are selected based on the calculation results of the three sets of loss sensitivity coefficients and real-time operating condition information: When the efficiency sensitivity of the transmission ratio is higher than that of the engine and motor, the transmission ratio should be adjusted first to reduce the transmission system loss; When the signs of the sensitivity of the engine and the motor are opposite, indicating that the direction of their contribution to efficiency is different, the torque transfer strategy is executed, that is, the engine load is reduced and compensated by the motor; When it is detected that the current mechanical loss rate exceeds the preset loss threshold, the gearbox ratio adjustment operation is temporarily frozen to prevent further deterioration of the gears and bearings under high loss conditions.

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