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

Abstract

The present application relates to the technical field of cooperative scheduling, in particular to a kind of engine and electric drive cooperative efficiency scheduling method based on target working condition interval, comprising the following steps: according to real-time demand power change rate and road gradient, match predefined target energy transmission chain interval;In target energy transmission chain interval, the total transmission efficiency model of output shaft to wheel end is constructed, and the total transmission efficiency model is associated with engine efficiency, electric drive efficiency and transmission chain loss rate;According to total transmission efficiency model, engine torque, motor torque and gearbox speed ratio are adjusted synchronously, so that energy transmission path loss is minimized.The present application constructs the target energy transmission chain interval determination logic of three-level combined type "basic interval+boundary scaling+loss constraint".Unlike the rough method based on only slope single parameter static division in the prior art, the scheme can dynamically adjust the available power range of transmission chain, effectively covering three typical operating states of flat road, climbing and heavy load.

Description

Technical Field

[0001] This invention relates to the field of collaborative scheduling technology, and in particular to a method for coordinated efficiency scheduling of engine and electric drive based on target operating condition intervals. Background Technology

[0002] The application of hybrid and electric drive systems in vehicle energy management is becoming increasingly common, and the power coordination between the engine and motor has become a key factor affecting vehicle energy consumption, response performance, and transmission stability. Traditional energy distribution strategies are mostly based on fixed operating condition mapping or rule-based control, often using single indicators such as engine load rate, battery SOC, and motor efficiency for switching decisions, lacking unified modeling and real-time evaluation of dynamic operating condition response characteristics and transmission chain loss characteristics.

[0003] On the one hand, existing methods typically determine the driving environment based on the driver's throttle opening or the slope, and select the engine, electric motor, or combined drive mode accordingly. However, this classification mostly relies on static empirical thresholds and fails to consider the impact of rapid changes in operating conditions on the stability of the energy path. Especially under acceleration, deceleration, or sudden slope changes, it can easily lead to lag in strategy switching, increased torque fluctuations, and even decreased energy efficiency.

[0004] On the other hand, efficiency models generally employ simplified forms, such as linear efficiency superposition or weighted averaging, failing to distinguish the independent contributions of electrical losses, mechanical losses, and engine parasitic losses. They also fail to establish a mathematical response relationship between total transmission efficiency and control variables, resulting in a lack of derivative-driven optimization capabilities in the control strategy. Furthermore, the thermal state of the transmission system, such as changes in gearbox oil temperature and structural losses, is not included in the scheduling constraints, posing an overload risk. Summary of the Invention

[0005] This invention provides a new scheduling method for engine and electric drive coordinated efficiency based on target operating condition range. It integrates dynamic identification of target operating condition range, multi-path loss modeling of transmission chain and derivative-driven optimization strategy to achieve efficient coordination of engine, electric drive system and transmission, thereby improving the overall vehicle energy efficiency and system stability.

[0006] A method for scheduling engine and electric drive cooperative efficiency based on a target operating condition range includes the following steps:

[0007] S1. Match a predefined target energy transfer chain interval based on the real-time demand power change rate and road slope;

[0008] S2. Within the target energy transmission chain range, construct a total transmission efficiency model from the output shaft to the wheel end, wherein the total transmission efficiency model is associated with engine efficiency, electric drive efficiency and transmission chain loss rate;

[0009] S3. Based on the overall transmission efficiency model, simultaneously adjust the engine torque, motor torque, and gearbox speed ratio to minimize energy transmission path losses.

[0010] 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. Based on the pre-division criteria 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.

[0011] Optionally, S1 further includes interval boundary correction, which involves scaling the initial interval of the selected target energy transfer chain interval based on the real-time demand power change rate.

[0012] Optionally, S1 further includes loss constraint verification, 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, then reverting to the initially selected interval.

[0013] Optionally, S2 specifically includes:

[0014] S21, within the locked target energy transfer chain range, obtain the engine basic efficiency value based on the engine speed-torque MAP. The basic efficiency value of the electric drive system is obtained based on the motor speed-torque MAP. ;

[0015] S22 calculates multiple types of loss rates in real time based on the current operating status of the transmission chain, including mechanical loss rate. Electrical loss rate and parasitic loss rate ;

[0016] S23, Construct the overall transmission efficiency model: ;in, The total transmission efficiency of the engine, electric drive, and transmission chain.

[0017] Optionally, the multi-category loss rate includes:

[0018] Mechanical loss rate This includes gear meshing efficiency loss and bearing friction loss, which can be obtained by referring to tables using the input shaft torque and oil temperature of the gearbox;

[0019] Electrical loss rate This includes Joule losses in power cables and switching losses in inverters, which are linearly fitted using the square of the drive current.

[0020] Parasitic loss rate This includes pumping losses and accessory power consumption, calibrated using engine intake pressure and battery voltage.

[0021] Optionally, S2 further includes loading operating condition constraints, specifically including injecting the boundary conditions of the target energy transfer chain interval as inequality constraints into the overall transfer efficiency model.

[0022] Optionally, S3 includes loss sensitivity analysis, specifically including analyzing the influence of engine torque, motor torque and gearbox speed ratio on total efficiency based on the constructed total transmission efficiency model. By calculating the efficiency response change trend separately, three sets of loss sensitivity coefficients are obtained to characterize the dependence of efficiency on each control variable.

[0023] Optionally, S3 further includes establishing a multi-parameter joint optimization model that maximizes efficiency by combining engine torque, motor torque, and gearbox ratio with the vehicle's required power as a constraint. The multi-parameter joint optimization model ensures that the total output traction force meets the vehicle's required power while maximizing the overall energy transfer efficiency from the source to the wheels, thus achieving optimal energy consumption control decisions.

[0024] Optionally, S3 further includes a dynamic execution strategy;

[0025] Based on the calculation results of the three sets of loss sensitivity coefficients and real-time operating information, different control strategies are selected:

[0026] When the efficiency sensitivity of the gearbox ratio is higher than that of the engine and motor, the gearbox ratio is adjusted first to reduce transmission system losses.

[0027] When the sensitivity signs of the engine and the motor are opposite, it indicates that their contributions to efficiency are in different directions. A torque transfer strategy is then implemented, which reduces the engine load and compensates for it with the motor.

[0028] When the current mechanical wear rate is detected to exceed the preset wear threshold, the gearbox speed ratio adjustment operation is temporarily frozen to prevent further deterioration of gears and bearings under high wear conditions.

[0029] The beneficial effects of this invention are:

[0030] This invention introduces a dual-parameter coupling mechanism of road gradient and demand power change rate to construct a three-level combined logic for determining the target energy transfer chain interval: "basic interval + boundary scaling + loss constraint". Unlike existing technologies that rely solely on static division based on a single parameter like gradient, this scheme dynamically adjusts the available power range of the drivetrain, effectively covering three typical operating states: flat roads, climbing slopes, and heavy loads. Simultaneously, the scaling ratio is adjusted based on an exponential model constructed from the power change rate and oil temperature, ensuring the dynamic response capability and thermal stability of the extended interval. This ensures that the scheduling strategy remains confined to a physically feasible, low-loss target interval, improving strategy robustness and energy efficiency adaptability.

[0031] This invention, in efficiency modeling, couples the efficiency and loss rates of the three energy paths—engine, motor, and transmission chain—in a chain, and independently decouples and models the three key loss factors—mechanical, electrical, and parasitic—achieving precise quantification through input shaft torque-oil temperature lookup tables, current square fitting, and intake pressure-voltage calibration, respectively. Compared to traditional linear weighted or black-box modeling methods, this approach more realistically reflects the energy dissipation process under different loads and operating conditions. By injecting target interval boundaries to form a constrained model, it eliminates model extrapolation errors, greatly improving the accuracy of energy consumption assessment and the controllability of strategies, providing a higher-resolution control basis for optimization.

[0032] This invention introduces efficiency partial derivative sensitivity indices for engine torque, motor torque, and gearbox ratio at the optimized execution layer, constructing a real-time control priority determination mechanism under multivariate response trends. Compared to traditional methods relying on empirical tables or power weighting, this solution enables fine-grained dynamic strategy selection, such as prioritizing gear shifting in scenarios dominated by gearbox efficiency, automatically shifting torque output load when engine and motor efficiency contributions are in opposite directions, and freezing gear ratio adjustment to protect structural safety under critical mechanical loss conditions. By combining derivative analysis with dynamic condition-driven mechanisms, the system can intelligently select the output path most beneficial to overall efficiency while meeting the vehicle's power requirements, achieving a high degree of synergistic balance between response speed, energy consumption control, and thermal safety. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the method steps in an embodiment of the present invention. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. For some well-known technologies, those skilled in the art may also use other alternative methods to implement the invention. Moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0036] like Figure 1 As shown, a method for scheduling engine and electric drive cooperative efficiency based on a target operating condition range includes the following steps:

[0037] S1. Match the predefined target energy transfer chain interval based on the real-time demand power change rate and road slope.

[0038] S1 specifically includes the following steps:

[0039] S11, Basic Section Selection: Select the basic section type based on the absolute value of the road slope, where:

[0040] When the absolute value of the slope When choosing a flat path for the transmission chain interval;

[0041] when When selecting the ramp transfer chain section;

[0042] when When selecting a heavy-load transfer chain interval.

[0043] Three basic interval divisions based on the absolute value of road slope (flat road, slope, heavy load):

[0044] Gradient is a key factor affecting vehicle mechanical loads, particularly longitudinal traction and gravity components. As the gradient increases, the required traction force of the vehicle increases non-linearly, leading to a significant increase in drivetrain load. Therefore, it is necessary to zone the vehicle according to gradient to match efficiency scheduling strategies under different load conditions.

[0045] In the field of vehicle dynamics and vehicle control, 5% and 10% gradients are often used as empirical thresholds for judging "light load," "medium load," and "heavy load" scenarios. Gradients within 5% are considered normal operating conditions, while gradients above 10% are considered heavy load climbing scenarios requiring high power output. These gradients are commonly used as a basis for classifying strategies such as transmission shift logic and engine operating condition adjustment.

[0046] On flat roads, the drive train primarily experiences smooth driving, with losses mainly stemming from internal friction and gear meshing efficiency. However, on slopes and under heavy loads, in addition to conventional losses, factors such as lateral gear forces and decreased lubrication efficiency due to temperature rise must also be considered. Therefore, using different ranges helps to describe energy transfer efficiency more precisely.

[0047] S12, Dynamic Boundary Correction: Based on Real-Time Demand Power Change Rate Boundary scaling is applied to each basic interval:

[0048] like Then the lower limit of the interval will be expanded. ;

[0049] like Then the upper limit of the interval will be compressed. .

[0050] The scaling factor is based on the following parameterized model: This formula represents the dynamic expansion or compression of the boundary of the working area of ​​the transfer chain; where, This represents the dynamic expansion / compression of the boundary of the transmission chain interval. Indicates the rate of change in power demand. Indicates the current transmission fluid temperature. This represents the interval response coefficient (a calibration parameter used to adjust model sensitivity). This represents the oil temperature decay coefficient (controlling the effect of oil temperature on boundary correction). Values ​​k = 0.12–0.18: adjust the response sensitivity of the range scaling; values ​​α = 0.015–0.02: oil temperature decay factor (approximately 1.5%–2% effect for every 1°C increase).

[0051] Real-time power demand change rate refers to the rate of change of the driving force power required by the vehicle per unit time, obtained from the vehicle controller (VCU) at the current moment. Power demand collected at two consecutive times , It can be approximated by the following formula: ;in, The sampling interval is denoted as .

[0052] The positive power change rate represents a vehicle in an acceleration state, where the system needs to rapidly transition from a static or low-load state to a high-load state. Continuing to use the original baseline range at this point may lead to decreased transmission efficiency due to insufficient power upper limit. Therefore, the lower limit of the range needs to be extended in advance to release more available low-speed, high-torque operating points for the engine or motor to choose from. During high-speed acceleration, the transient response caused by inertial loads is significant, and the traditional lower limit of the range is insufficient to accommodate the peak torque transmission chain. Therefore, by extending the lower limit by 10%–15%, the system is guided into a stronger power transmission region, meeting dynamic transition requirements and ensuring transmission efficiency. Based on multi-model tests, it was found that when the speed exceeds 4kW / s, not extending the lower limit will increase the risk of engine lag and frequent gearbox upshifts; while an extension of 10%–15% is an empirically optimized range for balancing response speed and transmission chain losses.

[0053] A negative power change rate indicates that the vehicle is in a coasting, deceleration, or braking condition, at which point the demand for drive power decreases rapidly. Maintaining the upper limit of the original range might cause the engine or motor to operate in an unnecessarily high-power range, reducing energy efficiency. When power is suddenly reduced under high load, if the upper limit is not contracted, 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 margin of 5% to 8% effectively controls energy waste without causing excessive jumps in system operating conditions that affect smoothness; this is a reasonable range for balancing response and stability in actual testing and debugging.

[0054] Example Verification 1: Extending the Lower Bound (Acceleration):

[0055] Current oil temperature ;

[0056] ;

[0057] Pick , ;

[0058] Substitute into the formula: If the lower limit of the original interval is 2.5kW, then: expansion ratio The percentage falls within the recommended range: 10%-15%.

[0059] Example Verification 2: Compression Limit (Slowdown):

[0060] Current oil temperature ;

[0061] ;

[0062] Take the same , ;

[0063] Substitute: If the upper limit of the original range is 2.5kW: compression ratio The recommended range is 5%-8%.

[0064] S13, Loss Constraint Verification: Estimate the transmission chain loss rate for the corrected target energy transfer chain interval. calculate:

[0065] like If so, it will revert to the corresponding base interval.

[0066] Among them, the loss rate threshold Related to transmission fluid temperature, it can be determined through the following compensation mechanism:

[0067] ;in, This indicates the estimated loss rate of the transmission chain. Temperature-corrected loss rate threshold This represents the baseline threshold (calibrated value 12%). This indicates the reference temperature (usually the calibration temperature of 60°C). This represents the oil temperature sensitivity coefficient (0.003 / °C).

[0068] S2. Within the target energy transmission chain range, construct a total transmission efficiency model from the output shaft to the wheel end, wherein the total transmission efficiency model is associated with engine efficiency, electric drive efficiency and transmission chain loss rate.

[0069] S2 specifically includes the following steps:

[0070] S21, Basic Efficiency Mapping: Within the locked target energy transfer chain interval:

[0071] Obtain the engine's basic efficiency value from the engine speed-torque MAP. ;

[0072] The basic efficiency value of the electric drive system is obtained by using a motor speed-torque MAP. .

[0073] The speed-torque map shows the engine / motor at different speeds. and output torque The operating efficiency matrix is ​​obtained through real vehicle calibration or bench testing. The basic efficiency value refers to the system's energy conversion efficiency under ideal conditions (no additional loads or losses). The specific acquisition process is as follows:

[0074] 1. Determine the current operating point and obtain the following real-time operating parameters from the vehicle control unit (VCU): Current engine / motor speed. , Current engine / motor torque , This operating point must be located within the currently locked target energy transfer chain interval.

[0075] 2: Call up the calibration efficiency map and preset the two-dimensional MAP table structure in the ECU or VCU:

[0076] Engine speed-torque efficiency graph;

[0077] Efficiency diagram of electric drive system (including the combined efficiency of motor and electronic control unit);

[0078] Each pair The input value corresponds to an efficiency output, which reflects the energy conversion rate at that point.

[0079] 3: Interpolation calculation efficiency, due to the current running point It may not fall exactly on a table node, so bilinear interpolation or higher-order interpolation is required:

[0080] Illustration: Bilinear interpolation if the current , It is located between the four points in the table below.

[0081] Table 1 Interpolation Diagram

[0082]

[0083] The interpolation formula is as follows:

[0084] ;

[0085] Applying this to the efficiency graphs of the engine and motor respectively, we obtain:

[0086] ;

[0087] ;

[0088] 4: Verify whether the current running point is within the target energy transfer chain interval; if it exceeds the interval boundary, discard the interpolation result and prompt to use the default efficiency or implement limit protection.

[0089] S22, Loss Path Quantification: Based on the current operating state of the transmission chain, calculate the following three types of independent loss rates:

[0090] S221, Mechanical Loss Rate This includes gear meshing efficiency loss and bearing friction loss, obtained from tables based on the transmission input shaft torque and transmission oil temperature; mechanical loss rate. The following is how to obtain it:

[0091] Data source:

[0092] Transmission input shaft torque Estimated using the powertrain torque sensor or engine output;

[0093] Transmission oil temperature Real-time data is collected via an oil temperature sensor.

[0094] A two-dimensional calibration table was pre-established (obtained through bench testing): ;

[0095] Horizontal axis of the table: Input torque (distribution range such as 0~400 Nm);

[0096] Vertical axis of the table: oil temperature (range, e.g., -20~120 °C);

[0097] Unit value: The transmission mechanical loss rate under the corresponding combination (the unit is a relative value, such as 0.03 representing 3%).

[0098] The higher the torque, the greater the lateral load on the gear mesh and bearing, and the higher the losses.

[0099] Low oil temperature will cause the viscosity of the lubricating oil to increase, which will lead to increased friction loss.

[0100] Excessive oil temperature will reduce lubrication performance and increase metal-to-metal contact loss;

[0101] The table lookup results reflect this type of nonlinear behavior.

[0102] S222, Electrical Loss Rate This includes Joule losses in power cables and switching losses in inverters, obtained by linear fitting of the square of the drive current. Electrical loss rate The following is how to obtain it:

[0103] Data source:

[0104] Motor phase current The RMS value is collected in real time by the motor controller (MCU) and is the three-phase average value.

[0105] Current data is used to reflect the load level and the Joule effect.

[0106] Fitting model formula Calibration coefficients were determined from experimental data under typical loads. The total power loss of the fitting cable, windings, and inverter is calculated. This represents the root mean square (RMS) value of the motor drive current, which is the average RMS value of the three-phase current. The fitting coefficients for the squared current term represent the Joule losses. Weighting of the impact on overall power loss This is a constant term, representing baseline losses independent of current, such as inverter static switching losses and standby losses.

[0107] Data construction method for fitting: collect current under different operating conditions Compare the total input / output power to calculate the instantaneous loss rate for each operating condition: ;by For the regression fitting of sample points, Let be the electrical loss rate at the i-th sampling point. Let be the electrical input power at the i-th operating point. Let be the motor output power at the i-th operating point; To construct a regression sample point set for fitting parameters .

[0108] Joule loss The dominant factor is proportional to the square of the current. Term b reflects the baseline consumption of the inverter, such as switching losses and standby losses. It is dynamically adjusted online to adapt to different ambient temperatures.

[0109] S223, Parasitic Loss Rate This includes engine pumping losses and electric drive accessory power consumption, obtained by referring to a calibration chart using engine intake pressure and battery voltage. Parasitic loss rate. The following is how to obtain it:

[0110] Data source:

[0111] Engine intake pressure : Taken from intake manifold pressure sensor (MAP);

[0112] Battery voltage It is adopted from the electric drive system BMS or main relay controller;

[0113] Preset two-dimensional joint calibration diagram: ; Reflects the engine's pumping load (large throttle opening) (Strong pumping effect) This indicates the load capacity affecting electric drive accessories (such as cooling pumps and air conditioning compressors). The joint calibration diagram is obtained from calibration on a vehicle bench. Higher engine load... The greater the pumping loss, the higher the battery voltage. The higher the accessory power, the clearer the additional loss components can be quantified by separating the engine and accessory load sources.

[0114] S23, Dynamic Coupling Modeling: The overall transfer efficiency model is constructed as follows:

[0115] ;

[0116] in, The total transmission efficiency of the engine, electric drive, and transmission chain.

[0117] This model divides the energy transfer path of the power system from the source (engine, electric drive) to the end (wheels) into three parts:

[0118] Engine path: Basic efficiency is However, it is also subject to parasitic losses such as pumping losses and accessory power consumption. The impact, therefore As an efficiency correction factor.

[0119] Electric drive path: The conversion efficiency of the motor itself is However, due to limitations in the heat loss and current fluctuation loss of components such as inverters and wires, the current is limited. Correction.

[0120] Transmission chain path: Mechanical systems such as gearboxes, differentials, and bearings experience friction and meshing losses, using... It characterizes the effective energy retention ratio.

[0121] These three paths are interconnected. A decrease in efficiency in any one path will amplify the overall loss. Therefore, a product structure is used to express the chain-like energy loss characteristics.

[0122] The vehicle power transmission process is essentially composed of multiple modules connected in series. Losses at each stage affect the energy supply to subsequent stages; therefore, efficiency should exhibit multiplicative decay rather than additive accumulation. Decoupling and modeling parasitic losses, electrical losses, and mechanical losses facilitates subsequent individual optimization of each stage, improving diagnostic accuracy and scheduling control capabilities. Incorporating dynamic operating parameters (torque, current, oil temperature) into the calculation of each loss factor helps the model adjust in real time according to environmental and load changes, maintaining predictive accuracy.

[0123] S24, Loading of operating condition constraints: The boundaries of the aforementioned target energy transfer chain interval (such as power, speed, load, etc.) are used as inequality constraints and injected into the above formula to limit the model to be valid only within the target interval, thus constructing a constrained model with interval constraints.

[0124] The boundary variables of the target energy transfer chain interval include the following dimensions:

[0125] Power range , max: The allowable power demand range within the interval;

[0126] Speed ​​range : The operating speed range of the engine / motor within the specified interval;

[0127] Torque range Output torque range within the interval

[0128] oil temperature range : Boundary conditions used to correct the effectiveness of the loss model.

[0129] Using the above boundary variables as the operating conditions of the model, we construct inequality constraints of the following form:

[0130] ;

[0131] These constraints apply to the time function The state variables are used to ensure that the model is only activated when the operating condition variables fall within the target range.

[0132] Using gating functions Whether the control model is enabled or not:

[0133] ;

[0134] Therefore, the constrained model is constructed as follows: That is, it is only used when all operating condition variables meet the target energy transfer chain interval requirements. Make subsequent scheduling decisions; otherwise, output 0.

[0135] S3. Based on the overall transmission efficiency model, simultaneously adjust the engine torque, motor torque, and gearbox speed ratio to minimize energy transmission path losses.

[0136] S3 specifically includes the following steps:

[0137] S31, Loss Sensitivity Analysis, in the Overall Transfer Efficiency Model In the middle, the engine torque is respectively Motor torque and gearbox ratio Calculate the partial derivatives to construct three sets of loss sensitivity coefficients:

[0138] ;

[0139] in:

[0140] This is the sensitivity coefficient of engine torque to overall efficiency; it represents the degree to which changes in engine torque affect overall transmission efficiency.

[0141] when At the same time, increasing engine torque will improve overall efficiency;

[0142] when At this time, the engine is currently in an inefficient range, and further increasing the torque will only reduce the overall efficiency;

[0143] It can be used to determine whether the engine should be "unloaded" and the load transferred to the electric motor.

[0144] This is the sensitivity coefficient of motor torque to overall efficiency; it represents the degree to which changes in motor torque affect the overall transmission efficiency.

[0145] This indicates that increasing the motor torque is beneficial to improving efficiency, and the motor is operating in its high-efficiency range.

[0146] This indicates that the motor is overloaded or in an inefficient region, and the motor load should be reduced.

[0147] By combining judgments with Ke, an "engine-motor coordinated" scheduling strategy can be formed.

[0148] This is the sensitivity coefficient of the gearbox ratio to the overall efficiency; it represents the degree of influence of gearbox ratio adjustment on the overall efficiency.

[0149] The current speed ratio is too low; increasing the speed ratio will help reduce transmission losses.

[0150] The current speed ratio is too high, which may cause excessive lateral force on the gears or slippage. It should be reduced.

[0151] If it is significantly greater than this, it indicates that the gearbox ratio is the dominant variable for efficiency optimization, and the system should prioritize adjusting the gear ratio. Significantly greater than , This indicates that the gearbox ratio is the dominant variable for efficiency optimization, and the system should prioritize adjusting the gear ratio.

[0152] The overall transmission efficiency calculated based on the aforementioned model, , , These are engine torque, electric motor torque, and the current gear ratio of the transmission, respectively.

[0153] S32, Node Collaboration Optimization: Setting Required Power As the main constraint, a multi-parameter joint optimization model is established:

[0154] It satisfies the following constraints: ;

[0155] in, This represents the current power requirement of the entire vehicle. For a fixed transmission ratio in a transmission system, This is the current vehicle speed. The equivalent torque output by the engine through the gearbox is constrained on the right end. This represents the total torque equivalent to that required for vehicle traction.

[0156] The above optimization objective is This indicates the search for engine torque under the current vehicle operating conditions. Motor torque Gearbox ratio The optimal combination maximizes the overall energy transfer efficiency of the vehicle. This efficiency encompasses all energy consumption characteristics of the engine, motor, and transmission system, and is a key indicator for measuring the overall energy consumption performance of the vehicle.

[0157] The constraints are This constraint means that the traction torque jointly output by the engine and motor through the transmission system must meet the current power demand target of the vehicle. This constraint requires that the resultant force output by the two together be equal to the traction torque required for the current operation of the vehicle.

[0158] S33, Execution Strategy: Based on the sensitivity coefficient and real-time operating conditions, execute the following dynamic decision-making logic:

[0159] Strategy 1: Prioritize gearbox ratio adjustment.

[0160] when The "Prioritize Gearbox Ratio Adjustment" condition indicates that, under the current operating conditions, a small change in the gearbox ratio has a greater impact on the overall system efficiency than a change in engine torque or electric motor torque. In other words, adjusting the gear ratio will more effectively improve efficiency. This is used to adjust the gear engagement point to optimize the energy transfer path when the current gear ratio has the greatest impact on efficiency.

[0161] At different speed ratios, gear meshing efficiency and bearing load change significantly. An incorrect speed ratio may lead to increased lateral force or torque mismatch. Especially in situations such as low-to-medium speed climbing and high-load start-up, speed ratio optimization can greatly reduce mechanical losses.

[0162] Decision logic: When it is identified that the gearbox ratio is most sensitive to efficiency, the gear ratio should be adjusted first rather than changing the power output structure. Actions such as upshifting or downshifting should be implemented to make the engine and motor operate in a more efficient speed-torque range.

[0163] Strategy 2, Engine-Motor Torque Transfer:

[0164] when Perform engine torque unloading and motor torque compensation;

[0165] This condition indicates that increasing engine torque has a negative impact on efficiency. Increasing the torque of the motor has a positive impact on efficiency. Since the two have opposite effects on system efficiency, a power transfer channel can be established to allow the high-efficiency source to take on more output under the condition of satisfying power constraints.

[0166] Engines are often inefficient when starting in cold temperatures, at high altitudes, or in non-economical areas, while electric motors are usually highly efficient in low to medium load areas and are suitable for providing transitional power support. This strategy is similar to the "energy efficiency diversion" mechanism and is an important control logic of hybrid systems.

[0167] Decision logic: Without changing the total output power, transfer more load to the more efficient component (motor); perform an "unloading" operation on the engine (reduce output torque), and the motor "compensates" for the shortfall.

[0168] Strategy 3, Transmission ratio freeze protection:

[0169] when Freeze gearbox ratio adjustment; used to protect the mechanical system from further disturbance under high-loss / high-temperature conditions, preventing bearing thermal failure or gear overload. .

[0170] Decision logic: Once the mechanical wear rate is detected... If the threshold is exceeded, immediately freeze the operation of changing the transmission speed ratio, prohibit the execution of commands such as shifting, skipping gears, and changing speed, and maintain the current state of operation.

[0171] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0172] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for scheduling the coordinated efficiency of engine and electric drive based on a target operating condition range, characterized in that, Includes the following steps: S1. Match a predefined target energy transfer chain interval based on the real-time demand power change rate and road slope; S2. Within the target energy transmission chain interval, construct a total transmission efficiency model from the output shaft to the wheel end. The total transmission efficiency model is associated with engine efficiency, electric drive efficiency, and transmission chain loss rate. The target energy transmission chain interval includes a flat road transmission chain interval, a ramp transmission chain interval, and a heavy-load transmission chain interval. Based on the pre-division criterion of the absolute value of the slope, select one of the flat road transmission chain interval, the ramp transmission chain interval, or the heavy-load transmission chain interval as the target energy transmission chain interval. Specifically, it includes: S21, within the locked target energy transfer chain range, obtain the engine basic efficiency value based on the engine speed-torque MAP. The basic efficiency value of the electric drive system is obtained based on the motor speed-torque MAP. ; S22 calculates multiple types of loss rates in real time based on the current operating status of the transmission chain, including mechanical loss rate. Electrical loss rate and parasitic loss rate ; S23, Construct the overall transmission efficiency model: ;in, The total transmission efficiency of the engine + electric drive + transmission chain; S3. Based on the overall transmission efficiency model, simultaneously adjust the engine torque, motor torque, and gearbox ratio to minimize energy transmission path losses. S3 also includes loss sensitivity analysis, specifically, based on the constructed total transmission efficiency model, analyzing the influence of engine torque, motor torque and gearbox speed ratio on total efficiency, and obtaining three sets of loss sensitivity coefficients by calculating the efficiency response change trend, which are used to characterize the dependence of efficiency on each control variable. S3 also includes a dynamic execution strategy; Based on the calculation results of the three sets of loss sensitivity coefficients and real-time operating information, different control strategies are selected: When the efficiency sensitivity of the gearbox ratio is higher than that of the engine and motor, the gearbox ratio is adjusted first to reduce transmission system losses. When the sensitivity signs of the engine and the motor are opposite, it indicates that their contributions to efficiency are in different directions. A torque transfer strategy is then implemented, which reduces the engine load and compensates for it with the motor. When the current mechanical wear rate is detected to exceed the preset wear threshold, the gearbox speed ratio adjustment operation is temporarily frozen to prevent further deterioration of gears and bearings under high wear conditions.

2. The method for scheduling engine and electric drive coordinated efficiency based on a target operating condition range according to claim 1, characterized in that, S1 also includes interval boundary correction, which scales the initial interval of the selected target energy transfer chain interval based on the real-time demand power change rate.

3. The method for scheduling engine and electric drive coordinated efficiency based on a target operating condition range according to claim 2, characterized in that, S1 also includes loss constraint verification, specifically including calculating the estimated transmission chain loss rate of the interval after the interval boundary correction. If the estimated transmission chain loss rate exceeds the loss rate threshold, it will revert to the initial selected interval.

4. The method for scheduling engine and electric drive coordinated efficiency based on a target operating condition range according to claim 3, characterized in that, The multi-category loss rates include: Mechanical loss rate This includes gear meshing efficiency loss and bearing friction loss, which can be obtained by referring to tables using the input shaft torque and oil temperature of the gearbox; Electrical loss rate This includes Joule losses in power cables and switching losses in inverters, which are linearly fitted using the square of the drive current. Parasitic loss rate This includes pumping losses and accessory power consumption, calibrated using engine intake pressure and battery voltage.

5. The method for scheduling engine and electric drive coordinated efficiency based on a target operating condition range according to claim 4, characterized in that, The S2 also includes loading operating condition constraints, specifically including injecting the boundary conditions of the target energy transfer chain interval as inequality constraints into the total transfer efficiency model.

6. The method for scheduling engine and electric drive coordinated efficiency based on a target operating condition range according to claim 1, characterized in that, The S3 also includes establishing a multi-parameter joint optimization model that maximizes efficiency by combining engine torque, motor torque, and gearbox ratio with the vehicle's required power as a constraint. The multi-parameter joint optimization model ensures that the total output traction force meets the vehicle's required power while maximizing the overall energy transfer efficiency from the source to the wheels, thus achieving optimal energy consumption control decisions.

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