Engine-battery thermal management system and sectional model predictive control method

Abstract

The invention discloses an engine-battery thermal management system and a sectional model prediction control method, and the system comprises a heat source and thermal load module which comprises an engine as a heat source and a power battery as a thermal load; the fluid driving module is used for driving the cooling liquid to circulate in the system; the fluid distribution and control module is used for adjusting the distribution proportion of the cooling liquid among different thermal management paths; the heat dissipation module is used for discharging redundant heat to the environment; the heat exchange module is used for realizing thermal coupling between the engine cooling liquid and the battery cooling liquid; wherein the fluid distribution and control module, the heat dissipation module and the heat exchange module work cooperatively to form a plurality of parallel heat flow paths, so that engine waste heat is distributed, regulated and controlled between a battery preheating path and a main heat dissipation path according to needs. Through the cooperation of the multi-channel adjustable heat management structure and the sectional type model prediction control method, the heat management energy efficiency of the hybrid electric vehicle in the low-temperature environment is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of thermal management of new energy vehicles, and particularly relates to an engine-battery thermal management system and a segmented model predictive control method. Background Technology

[0002] In low-temperature environments, the internal resistance of power batteries in new energy vehicles increases and their electrochemical performance degrades, while the engine experiences low cold-start efficiency and significant wear. To address this, the industry has proposed an engine-battery coupled thermal management system, which aims to recover waste heat from the engine to preheat the battery through valve and circuit switching, thereby reducing electric auxiliary heating energy consumption and improving the system's low-temperature performance.

[0003] Existing systems typically employ cooling architectures based on a single thermostat or simple valve assemblies. Their operating mode is fixed: cooling is shut off when the engine is cold to accelerate engine warm-up; once the engine coolant temperature exceeds a set threshold, valves are switched to direct some heat to the battery heat exchanger. While simple, this structure suffers from a single heat distribution path, failing to allow for continuous and precise adjustments based on actual battery needs and engine operating conditions. This results in significant waste heat being ineffectively lost, leading to low heat recovery efficiency.

[0004] In terms of control strategies, current systems generally adopt rule-based control (such as on / off control and proportional regulation) based on fixed temperature thresholds. This method easily causes actuators such as pumps and valves to operate frequently near the threshold, generating oscillations, which impairs control stability and actuator lifespan, and also consumes a lot of energy. Although some studies have attempted to apply advanced algorithms such as model predictive control (MPC), they mostly have significant limitations: First, the single-stage, uniform weight optimization framework fails to distinguish the timing differences between "the engine needs to heat up rapidly" and "the battery needs to preheat gradually," leading to improper thermal coordination; second, the models are often oversimplified, making it difficult to accurately describe the complex nonlinear coupling and actuator interactions between multiple loops; third, there is a lack of collaborative optimization for multiple actuators such as pumps, valves, and fans, and each component often operates independently, resulting in low overall system energy efficiency and poor dynamic response.

[0005] Therefore, existing coupled thermal management systems have insufficient structural adjustment capabilities and limited levels of intelligence and coordination in control, making it difficult to achieve efficient waste heat recovery and precise and stable temperature control under complex low-temperature conditions. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides an engine-battery thermal management system, comprising:

[0007] The heat source and heat load module includes the engine as the heat source and the power battery as the heat load;

[0008] A fluid drive module, connected to the heat source and heat load module, is used to drive the coolant to circulate within the system;

[0009] The fluid distribution and control module is connected in the loop formed by the heat source and heat load module and the fluid drive module, and is used to adjust the distribution ratio of coolant between different thermal management paths.

[0010] A heat dissipation module, connected to the fluid distribution and control module, is used to discharge excess heat into the environment;

[0011] A heat exchange module is connected between the heat source and heat load module and the fluid distribution and control module to achieve thermal coupling between the engine coolant and the battery coolant.

[0012] The fluid distribution and control module, the heat dissipation module, and the heat exchange module work together to form multiple parallel heat flow paths. Through continuous adjustment by the fluid distribution and control module, the waste heat of the engine is distributed and controlled on demand between the battery preheating path and the main heat dissipation path.

[0013] Optionally, the fluid drive module includes:

[0014] The engine water pump is installed on the engine cooling main circuit and is used to drive the circulation of coolant flowing through the engine.

[0015] The battery water pump is installed on the power battery thermal management circuit to drive the circulation of coolant flowing through the power battery.

[0016] Optionally, the fluid distribution and control module includes multiple control valves, specifically including:

[0017] The engine control valve is located on the main pipeline after the engine coolant outlet. It serves as a main distributor valve to distribute coolant to different downstream branches.

[0018] An engine heat exchange valve is connected between a downstream branch of the engine control valve and the engine-side inlet of the heat exchange module, and is used to control the proportion of coolant entering the heat exchange module to preheat the battery.

[0019] An engine cooling valve is connected between another downstream branch of the engine control valve and the engine radiator inlet of the cooling module, and is used to control the proportion of coolant entering the cooling module to achieve heat dissipation.

[0020] A battery cooling valve is installed on the power battery thermal management circuit to control the flow path of battery coolant into the battery radiator of the heat dissipation module.

[0021] Optionally, the heat dissipation module includes:

[0022] The engine radiator has its inlet connected to the engine cooling valve and its outlet connected to the engine coolant inlet, and is used to dissipate heat from the engine coolant.

[0023] The battery radiator has its inlet connected to the battery cooling valve and its outlet connected to the power battery coolant inlet, and is used to dissipate heat from the power battery coolant.

[0024] An engine fan is correspondingly installed on the engine radiator to assist the engine radiator in dissipating heat.

[0025] A battery fan is installed on the battery heat sink to assist in heat dissipation.

[0026] Optionally, the heat exchange module is a heat exchanger with independent engine coolant channels and battery coolant channels, used to transfer engine waste heat to the battery circuit without mixing the coolants.

[0027] The present invention also provides a segmented model predictive control method based on the aforementioned engine-battery thermal management system, comprising the following steps:

[0028] Based on the physical characteristics of the thermal management system, a system prediction model is established that can reflect the thermal dynamics of the engine, the thermal dynamics of the battery, and the coupling relationship between multiple loops.

[0029] Based on the real-time temperature status of the engine and battery, a piecewise optimization objective function is set, which includes engine temperature target and battery temperature target. The optimization objective function can dynamically adjust the optimization weights of engine temperature target and battery temperature target as the temperature status changes.

[0030] In each control cycle, based on the system prediction model and the current system state, the piecewise optimization objective function is solved by rolling optimization to obtain the optimal control sequence of multiple actuators in a future time domain.

[0031] The instantaneous control quantities in the optimal control sequence are output to each actuator of the thermal management system to control the distribution, circulation and heat dissipation of the coolant.

[0032] In the next control cycle, the system state is updated and the rolling optimization solution and output process is repeated.

[0033] Optionally, establishing the system prediction model specifically includes:

[0034] Based on the structural parameters and heat transfer characteristics of the thermal management system, a system prediction model is established with engine coolant temperature and battery temperature as state variables. The system prediction model can describe the dynamic influence of the control input of each actuator on the system temperature state.

[0035] Optionally, the dynamic adjustment and optimization of weights specifically includes:

[0036] When the engine temperature is lower than its preset first temperature threshold, the weight of the engine temperature target in the optimization objective function is increased to prioritize ensuring rapid engine warm-up.

[0037] When the engine temperature reaches or exceeds the first temperature threshold and the battery temperature is lower than its target temperature, the weight of the battery temperature target in the optimization objective function is gradually increased to achieve the transfer of engine waste heat to the battery circuit.

[0038] Optionally, the rolling optimization solution specifically includes:

[0039] The engine water pump speed, the battery water pump speed, the engine control valve opening, the engine heat exchange valve opening, the engine cooling valve opening, the battery cooling valve opening, the engine fan power, and the battery fan power are all used as decision variables for collaborative optimization and solved, while taking into account the physical constraints of each decision variable during the solution process.

[0040] Optionally, the obtained optimal control sequence is used to make the opening control commands of the engine control valve, the engine heat exchange valve, the engine cooling valve, and the battery cooling valve present as control quantities that change continuously and smoothly over time.

[0041] Compared with the prior art, the present invention has the following advantages and technical effects:

[0042] 1. Significantly improves engine waste heat utilization efficiency and system low-temperature adaptability:

[0043] By employing a multi-channel adjustable coupling structure with added engine heat exchange valve and engine cooling valve, this invention achieves continuous proportional regulation of heat flow between engine cooling, battery preheating, and the bypass circuit. This structure fundamentally overcomes the limitation of fixed heat flow paths in traditional single-valve structures, allowing waste heat generated by the engine to be precisely and on-demand distributed to the battery preheating circuit based on the real-time temperature requirements of the battery and the engine's thermal load. This significantly reduces energy loss due to ineffective dissipation of waste heat into the environment while the battery still needs preheating, thereby significantly improving the effective recovery rate of engine waste heat in low-temperature environments, enhancing battery heating efficiency, and improving the overall low-temperature adaptability of the system.

[0044] 2. Achieve high-precision and high-stability temperature control, effectively eliminating actuator oscillation:

[0045] By introducing piecewise model predictive control (MPC) to replace traditional threshold-based rule control, this invention utilizes a built-in predictive model and rolling optimization mechanism to proactively estimate the system's thermal state change trend and calculate smooth, continuous optimal control commands accordingly. This transforms the operation of actuators such as pumps, valves, and fans from discrete switching modes to continuous regulation modes, fundamentally avoiding high-frequency start-stop and oscillation phenomena caused by temperature fluctuations near thresholds. This not only significantly improves the control accuracy and steady-state maintenance capability of engine and battery temperatures but also significantly reduces actuator wear, system noise, and unnecessary energy consumption.

[0046] 3. Achieve time-sequential coordinated optimal control of the engine and battery heating process:

[0047] By constructing a segmented MPC framework and setting dynamically adjustable phased optimization objectives, this invention enables the control system to intelligently identify and match the timing characteristics of the engine's "rapid warm-up" and the battery's "delayed preheating." During the cold start phase, it automatically prioritizes ensuring the engine's warm-up rate. Once the engine temperature reaches its efficient operating range, it smoothly shifts the control focus to battery preheating, achieving an orderly, relay-style transfer of heat. This time-sequential collaborative control strategy ensures that the thermal management process conforms to physical laws, avoids warm-up delays or efficiency reductions caused by competition between the two objectives, and maximizes the overall thermal efficiency of the system.

[0048] 4. Achieve global collaborative optimization among multiple actuators to improve overall system energy efficiency:

[0049] By incorporating the engine water pump, battery water pump, multiple control valves, and cooling fans into a unified MPC optimization framework for collaborative solution, this invention achieves global coordination and overall optimal planning for the actions of all actuators. Based on real-time thermal load, the system can comprehensively decide on the flow rate, heat distribution ratio, and heat dissipation intensity of each loop, thereby avoiding the problem of unreasonable energy distribution caused by "local optimization, overall conflict." This global collaborative mechanism ensures a dynamic balance and most economical allocation of heat among engine warm-up, battery preheating, and environmental heat dissipation, significantly improving the overall energy efficiency and dynamic response quality of the entire thermal management system. Attached Figure Description

[0050] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0051] Figure 1 This is a schematic diagram of the improved engine-battery coupled thermal management system provided in an embodiment of the present invention;

[0052] Figure 2The above are the actuator output characteristic curves of the improved structure in the embodiment of the present invention under the rule control strategy and the ambient temperature of -20℃. Among them, (a) is the curve of the speed change of the engine and the battery water pump, (b) is the curve of the opening change of the engine control valve and the engine heat exchange valve, (c) is the curve of the opening change of the engine cooling valve and the battery cooling valve, and (d) is the curve of the opening change of the engine and the battery fan.

[0053] Figure 3 The above are comparison curves of battery preheating efficiency between the traditional structure and the improved structure under FTP-75 conditions in the embodiments of the present invention. (a) is a comparison curve under -5℃ environment, (b) is a comparison curve under -10℃ environment, (c) is a comparison curve under -15℃ environment, and (d) is a comparison curve under -20℃ environment.

[0054] Figure 4 This is a schematic diagram of the co-simulation platform used in an embodiment of the present invention;

[0055] Figure 5 The figures shown are the actuator output characteristic curves of the improved structure in the embodiment of the present invention under the segmented MPC control strategy and the ambient temperature of -20℃. Among them, (a) is the curve of the speed change of the engine and the battery water pump, (b) is the curve of the opening change of the engine control valve and the engine heat exchange valve, (c) is the curve of the opening change of the engine cooling valve and the battery cooling valve, and (d) is the curve of the opening change of the engine and the battery fan.

[0056] Figure 6 The figure shows the temperature regulation effect curves of the segmented MPC control strategy in the embodiment of the present invention under FTP-75 conditions and -20℃ environment, where (a) is the curve of engine coolant temperature and relative error change, and (b) is the curve of battery temperature and relative error change. Detailed Implementation

[0057] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0058] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0059] Example 1

[0060] like Figure 1 As shown, this embodiment provides an engine-battery thermal management system capable of performing functions such as heat source supply, coolant drive, flow regulation, and air cooling, including:

[0061] The heat source and heat load module includes the engine as the heat source and the power battery as the heat load;

[0062] A fluid drive module, connected to the heat source and heat load module, is used to drive the coolant to circulate within the system;

[0063] The fluid distribution and control module is connected in the loop formed by the heat source and heat load module and the fluid drive module, and is used to adjust the distribution ratio of coolant between different thermal management paths.

[0064] A heat dissipation module, connected to the fluid distribution and control module, is used to discharge excess heat into the environment;

[0065] A heat exchange module is connected between the heat source and heat load module and the fluid distribution and control module to achieve thermal coupling between the engine coolant and the battery coolant.

[0066] The fluid distribution and control module, the heat dissipation module, and the heat exchange module work together to form multiple parallel heat flow paths. Through continuous adjustment by the fluid distribution and control module, the waste heat of the engine is distributed and controlled on demand between the battery preheating path and the main heat dissipation path.

[0067] The feasible heat source and heat load modules include:

[0068] Engine: The main heat source of the system, providing waste heat that can be used to preheat the battery.

[0069] Power batteries: the main heat load objects, need to be rapidly raised to the target temperature range in low-temperature environments.

[0070] Implementable, the fluid drive module includes:

[0071] The engine water pump is installed on the engine cooling main circuit and is used to drive the circulation of coolant flowing through the engine; the battery water pump is installed on the power battery thermal management circuit and is used to drive the circulation of coolant flowing through the power battery.

[0072] Furthermore, the engine and battery water pump (P SE P SB It can drive the liquid circulation of the engine and battery circuit and ensure that the two exchange heat.

[0073] Implementably, the fluid distribution and control module includes multiple control valves, specifically including:

[0074] The engine control valve is located on the main pipeline after the engine coolant outlet. It serves as a main distributor valve to distribute coolant to different downstream branches.

[0075] An engine heat exchange valve is connected between a downstream branch of the engine control valve and the engine-side inlet of the heat exchange module, and is used to control the proportion of coolant entering the heat exchange module to preheat the battery.

[0076] An engine cooling valve is connected between another downstream branch of the engine control valve and the engine radiator inlet of the cooling module, and is used to control the proportion of coolant entering the cooling module to achieve heat dissipation.

[0077] A battery cooling valve is installed on the power battery thermal management circuit to control the flow path of battery coolant into the battery radiator of the heat dissipation module.

[0078] It is feasible; the system employs eight key actuators for liquid or air flow regulation, four of which are key valves:

[0079] Engine control valve (V OE1 ): Engine outlet main distributor valve, used to determine the primary proportion of coolant entering each branch.

[0080] Engine heat exchange valve (V OE2 The control mechanism controls the proportion of coolant entering the battery preheating coupling circuit, and is the core actuator for transferring engine waste heat to the battery side.

[0081] Engine cooling valve (V OE3 ): Controls the proportion of coolant entering the main heat dissipation circuit to achieve precise heat dissipation and overheat protection.

[0082] Battery thermal valve (V OB ): Controls whether battery coolant enters the battery-side heat dissipation path.

[0083] Implementable, the heat dissipation module includes:

[0084] The engine radiator has its inlet connected to the engine cooling valve and its outlet connected to the engine coolant inlet, and is used to dissipate heat from the engine coolant.

[0085] The battery radiator has its inlet connected to the battery cooling valve and its outlet connected to the power battery coolant inlet, and is used to dissipate heat from the power battery coolant.

[0086] Engine fan (F OE ( ), correspondingly installed on the engine radiator, used to increase the airflow of the engine radiator, for the main heat dissipation path;

[0087] Battery Fan (F) OB ( ), correspondingly set on the battery heat sink, to assist the battery heat sink in heat dissipation and achieve necessary forced air cooling.

[0088] Implementable, the heat exchange module is a heat exchanger with independent engine coolant channels and battery coolant channels, used to transfer engine waste heat to the battery circuit without mixing coolants.

[0089] As a feasible implementation method, the thermal management structure designed in this embodiment includes an engine preheating circuit, an engine cooling circuit, a battery preheating circuit, a battery cooling circuit, and an engine heat exchange circuit. A multi-valve diversion unit continuously regulates the coolant. When the engine is cold, the valves automatically adjust to ensure the coolant primarily circulates within the engine, accelerating temperature rise. Once the engine reaches the target temperature, the system gradually activates the battery heating circuit, directing excess engine heat to the battery heat exchanger for controllable preheating. When there is excess heat, the system activates the cooling circuit to dissipate excess heat into the engine radiator, ensuring overall temperature balance.

[0090] Specifically, the system adopts a multi-loop parallel structure, and the distribution ratio of coolant in different paths is determined by valve coordination. The connection relationship of each loop is as follows:

[0091] ① Engine cooling main circuit:

[0092] Coolant flows out from the engine outlet and is pumped by the engine water pump (P). SE Driven by ) and entering the engine control valve (V) via the main pipeline. OE1 V OE1 As a main flow divider, its output is distributed to the following two core branches:

[0093] a. Battery preheating coupling circuit:

[0094] Coolant passes through the engine heat exchange valve (V OE2 The heat flows to the heat exchanger and is thermally coupled with the battery circuit to transfer the engine's waste heat to the battery.

[0095] b. Main heat dissipation circuit:

[0096] Coolant passes through the engine cooling valve (V OE3 ) enters the radiator and is fed by the engine fan (F OE (Auxiliary heat dissipation) and then return to the engine inlet.

[0097] V OE2 With V OE3 The opening ratio together determines the flow distribution of engine waste heat in the two paths of "preheating battery" and "heat dissipation and cooling", which is the key to the structure of this system.

[0098] ② Battery thermal management circuit:

[0099] Coolant enters the battery water pump (P) from the battery pack outlet.SB ), and is driven into the following two paths:

[0100] a. Heat exchanger loop (preheating preferred):

[0101] The coolant flows to the heat exchanger, absorbs the engine's waste heat, and then returns to the battery, achieving active heating in low-temperature environments.

[0102] b. Battery heat dissipation circuit (activated when cooling is required):

[0103] When the battery temperature is high, the coolant flows through the battery heat dissipation valve (V OB The current is diverted to the battery heat sink, and then to the battery fan (F). OB After auxiliary heat dissipation, the heat is returned to the battery.

[0104] ③ The collaborative mechanism of the newly added heat exchange loop:

[0105] This embodiment adds two key valves: the engine heat exchange valve (V) OE2 ) and engine cooling valve (V OE3 They always work together during system operation: V OE2 Determines the proportion of engine waste heat entering the battery preheating path; V OE3 Determining the proportion of engine waste heat entering the radiator for heat dissipation; the coordinated operation of the two valves to achieve optimal distribution of engine waste heat is the core of this system's efficient low-temperature preheating.

[0106] Through the above structure, the system forms a multi-path heat flow network consisting of an engine preheating circuit, an engine cooling circuit, a battery preheating circuit, a battery cooling circuit, and an engine heat exchange circuit, thereby realizing the quantitative distribution and phased adjustment of waste heat.

[0107] On the other hand, this embodiment also provides a segmented model predictive control method based on an engine-battery thermal management system, including the following steps:

[0108] Based on the physical characteristics of the thermal management system, a system prediction model is established that can reflect the thermal dynamics of the engine, the thermal dynamics of the battery, and the coupling relationship between multiple loops.

[0109] Based on the real-time temperature status of the engine and battery, a piecewise optimization objective function is set, which includes engine temperature target and battery temperature target. The optimization objective function can dynamically adjust the optimization weights of engine temperature target and battery temperature target as the temperature status changes.

[0110] In each control cycle, based on the system prediction model and the current system state, the piecewise optimization objective function is solved by rolling optimization to obtain the optimal control sequence of multiple actuators in a future time domain.

[0111] The instantaneous control quantities in the optimal control sequence are output to each actuator of the thermal management system to control the distribution, circulation and heat dissipation of the coolant.

[0112] In the next control cycle, the system state is updated and the rolling optimization solution and output process is repeated.

[0113] The feasible method for establishing a system prediction model specifically includes:

[0114] Based on the structural parameters and heat transfer characteristics of the thermal management system, a system prediction model is established with engine coolant temperature and battery temperature as state variables. The system prediction model can describe the dynamic influence of the control input of each actuator on the system temperature state.

[0115] The feasible dynamic adjustment and optimization of weights specifically includes:

[0116] When the engine temperature is lower than its preset first temperature threshold, the weight of the engine temperature target in the optimization objective function is increased to prioritize ensuring rapid engine warm-up.

[0117] When the engine temperature reaches or exceeds the first temperature threshold and the battery temperature is lower than its target temperature, the weight of the battery temperature target in the optimization objective function is gradually increased to achieve the transfer of engine waste heat to the battery circuit.

[0118] The feasible method, namely the rolling optimization solution, specifically includes:

[0119] The engine water pump speed, the battery water pump speed, the engine control valve opening, the engine heat exchange valve opening, the engine cooling valve opening, the battery cooling valve opening, the engine fan power, and the battery fan power are all used as decision variables for collaborative optimization and solved, while taking into account the physical constraints of each decision variable during the solution process.

[0120] The obtained optimal control sequence is feasible, and is used to make the opening control commands of the engine control valve, the engine heat exchange valve, the engine cooling valve and the battery cooling valve present as control quantities that change continuously and smoothly over time.

[0121] The segmented MPC control strategy designed in this embodiment models and optimizes the temporal characteristics of the engine and battery thermal management processes in stages, enabling the controller to dynamically adjust optimization objectives and actuator constraints according to the temperature requirements of different stages. During the engine cold-start phase, the controller increases the weight of the engine temperature target, prioritizing rapid engine warm-up by optimizing pump speed and valve opening. Once the engine reaches a stable temperature range, the controller automatically switches to the battery preheating phase, increasing the optimization priority of the battery temperature target and allocating more heat flow to the battery circuit for gradual waste heat heating. This segmented MPC method achieves temporal and forward-looking optimization control of dual objectives through stage switching and dynamic weight adjustment, significantly improving the system's temperature control accuracy and stability.

[0122] On the other hand, this embodiment also provides a co-simulation platform based on AMESim–MATLAB / Simulink, such as Figure 4 As shown, a full-process verification was conducted under the FTP-75 standard dynamic operating conditions. The implementation approach included two phases: first, comparing the battery preheating capabilities of the improved and traditional structures under a unified rule control strategy to demonstrate the advantages of the improved system; then, based on the improved structure, introducing the segmented MPC control method of this embodiment, and evaluating its comprehensive regulation effect on engine coolant temperature and battery temperature.

[0123] (1) Simulation platform and model construction:

[0124] This embodiment constructs physical models of the engine cooling system, battery cooling system, heat exchange circuit, heat dissipation circuit, water pump, and valves in AMESim. The AMESim model provides realistic dynamic responses such as coolant flow rate, heat generation, and heat exchange efficiency.

[0125] The control strategy is built in MATLAB / Simulink, including a unified rule controller and the segmented MPC controller in this embodiment. AMESim and Simulink exchange coolant temperature, flow rate, and valve commands in real time through an interface module.

[0126] The entire simulation process uses the FTP-75 driving cycle as the heat load input, so that the engine generates real coolant temperature changes during the full dynamic process of acceleration, constant speed, deceleration and idling.

[0127] (2) Phase 1: Comparison of battery preheating efficiency based on unified rule control strategy:

[0128] To ensure fairness in the structural comparison, a unified rule-based control strategy was implemented. This rule-based control employed a uniform threshold logic: priority was given to heating when the engine temperature was <85℃; the battery preheating path was activated when the engine temperature was ≥85℃ and the battery temperature was <25℃; and the radiator and fan were activated when the engine temperature was ≥95℃. Under this unified rule-based control, the battery preheating efficiency of the improved structure and the traditional structure was compared.

[0129] (3) Phase Two: Introducing a segmented MPC control strategy based on the improved structure:

[0130] Building upon the improved structure, this embodiment further designs a piecewise model predictive control (MPC) method suitable for dynamic operating conditions. A state-space predictive model, i.e., the system predictive model, is established based on AMESim's multi-input multi-output (MIMO) thermal system response data. Joint control of multiple actuators is achieved through rolling optimization. MPC automatically adjusts the optimization weights to form a piecewise control strategy based on the engine and battery temperature requirements at different stages: prioritizing rapid engine warm-up during the cold start phase; subsequently, the battery temperature weight is gradually increased to achieve stable preheating. Thanks to the constraint management capabilities of the model predictive framework, MPC can still stably output continuous control quantities under actuator constraints such as valve opening, pump speed, and fan power, avoiding the jumps and oscillations common in rule-based control. Simultaneously, the multi-actuator collaborative adjustment capability is significantly enhanced, enabling the system to maintain stable heat distribution and temperature trajectory tracking under dynamic operating conditions.

[0131] (4) Comprehensive comparison and verification between Phase 1 and Phase 2:

[0132] To comprehensively evaluate the combined effect of the structure and control strategy proposed in this embodiment, the results show that: Figure 3 As shown, the improved thermal management system structure achieves dynamic multi-channel heat flow distribution by introducing engine heat exchange valves and cooling valves. Compared with the traditional structure, the time required to preheat the battery from -5℃ to -20℃ to 25℃ under FTP-75 conditions is reduced by more than 61%, significantly improving the efficiency of engine waste heat utilization. Furthermore, the designed multivariable piecewise model predictive controller exhibits significant advantages in multi-actuator coordinated adjustment, reference trajectory tracking, and constraint management. For example... Figure 2 , Figure 5 and Figure 6 As shown, the segmented MPC strategy can achieve a stable battery preheating process while ensuring rapid engine warm-up, with relative errors of less than 1%, and avoids high-frequency oscillations of the actuator. Its energy utilization efficiency and system robustness are superior to the rule-based control strategy.

[0133] This embodiment constructs a coordinated temperature control system for the engine and battery under complex operating conditions by introducing a multi-channel adjustable coupling structure, dual-objective piecewise model predictive control (MPC), and a multi-actuator collaborative adjustment mechanism. Compared with existing technologies, this embodiment has significant advantages in waste heat utilization efficiency, temperature control accuracy, control stability, and energy management efficiency, specifically in the following aspects:

[0134] (1) Significantly improves waste heat utilization capacity and adaptability to low-temperature environments:

[0135] This embodiment adds an engine heat exchange valve (V) to the traditional cooling structure. OE2 ) and engine cooling valve (V OE3 A multi-channel heat flow distribution structure with continuously proportional adjustment was constructed, enabling the engine waste heat to be distributed as needed between the battery preheating path and the main heat dissipation path. Test results show that the system can significantly improve the effective utilization rate of engine waste heat in low-temperature environments, and improve the battery preheating efficiency by more than 61% under FTP-75 conditions, effectively overcoming the problems of limited heat flow paths and insufficient waste heat utilization in existing single-valve structures.

[0136] (2) Improve temperature control accuracy and avoid oscillation problems in traditional rule control:

[0137] This embodiment employs segmented MPC to replace the traditional threshold-based rule-based control strategy. This transforms the outputs of actuators such as valves, pumps, and fans from discrete switching logic into smooth, continuous optimal control quantities, fundamentally reducing frequent actuator jumps and the resulting temperature fluctuations. Experimental results show that the steady-state temperature control accuracy of the engine and battery can be stably maintained within ±1%, and actuator oscillations are significantly reduced. This effectively solves the technical defects of rule-based control, such as hysteresis, jitter, and high-frequency oscillations, and significantly improves the system's temperature control stability and response quality.

[0138] (3) Achieve time-sequential and collaborative optimization control of the engine-battery dual objectives:

[0139] The segmented MPC control framework constructed in this embodiment can automatically switch control stages according to the temperature requirements of the engine and battery under different operating conditions. During the cold start stage, it prioritizes rapid engine warm-up, and gradually increases the battery preheating weight after the engine reaches a stable operating range. This method effectively avoids the problem of mutual interference between the engine and battery targets in traditional single-stage control, achieving a coordinated heating process that conforms to physical laws and significantly improving the overall coordination of the coupled thermal management system.

[0140] (4) Achieve unified optimization of multiple actuators and improve the overall energy efficiency of the system:

[0141] This embodiment incorporates key actuators such as water pumps, valves, and fans into the same MPC optimization framework. Through multi-variable collaborative adjustment, it achieves the overall optimal configuration of coolant flow, heat flow distribution, and heat dissipation capacity, thereby avoiding repetitive actions or energy waste caused by traditional independent control. This effectively reduces redundant heat dissipation and unnecessary energy loss, significantly improving system operating efficiency.

[0142] (5) Improve system controllability, response speed and robustness:

[0143] Because MPC possesses predictive and rolling optimization capabilities, this embodiment can adjust the control strategy in advance based on future changes in thermal load, ensuring stable control performance under acceleration, hill climbing, rapid load changes, and low-temperature cooling environments. In typical FTP-75 dynamic operating conditions, the relative temperature error between the engine and battery is less than 1%, significantly enhancing the system's adaptability to ambient temperature changes. Simultaneously, the segmented control method further improves the controller's robustness, giving the system stronger disturbance rejection capabilities and faster response speed, meeting the stable and reliable thermal management requirements under complex operating conditions.

[0144] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An engine-battery thermal management system, characterized by, The system comprises: a heat source and heat load module, including an engine as a heat source and a power battery as a heat load; a fluid driving module connected to the heat source and heat load module for driving the circulation of coolant in the system; a fluid distribution and control module connected in the loop formed by the heat source and heat load module and the fluid driving module for adjusting the distribution ratio of coolant among different heat management paths; a heat dissipation module connected to the fluid distribution and control module for discharging excess heat to the environment; a heat exchange module connected between the heat source and heat load module and the fluid distribution and control module for realizing the thermal coupling between engine coolant and battery coolant; wherein the fluid distribution and control module, the heat dissipation module and the heat exchange module work together to form multiple parallel heat flow paths, and through the continuous adjustment of the fluid distribution and control module, the engine waste heat is distributed and regulated between the battery preheating path and the main heat dissipation path as needed.

2. The engine-battery thermal management system of claim 1, wherein, The fluid driving module comprises: an engine water pump arranged on the engine cooling main circuit for driving the circulation of coolant flowing through the engine; a battery water pump arranged on the power battery heat management circuit for driving the circulation of coolant flowing through the power battery.

3. The engine-battery thermal management system of claim 1, wherein, The fluid distribution and control module comprises a plurality of control valves, specifically including: an engine control valve arranged on the main pipeline after the engine coolant outlet, serving as a total flow distribution valve for distributing coolant to different downstream branches; an engine heat exchange valve connected between one downstream branch of the engine control valve and the engine side inlet of the heat exchange module for controlling the proportion of coolant entering the heat exchange module to realize battery preheating; an engine heat dissipation valve connected between another downstream branch of the engine control valve and the engine radiator inlet of the heat dissipation module for controlling the proportion of coolant entering the heat dissipation module to realize heat dissipation; a battery heat dissipation valve arranged on the power battery heat management circuit for controlling the flow of battery coolant into the battery radiator path of the heat dissipation module.

4. The engine-battery thermal management system of claim 3, wherein, The heat dissipation module comprises: an engine radiator with its inlet connected to the engine heat dissipation valve and its outlet connected to the engine coolant inlet for dissipating heat from the engine coolant; a battery radiator with its inlet connected to the battery heat dissipation valve and its outlet connected to the power battery coolant inlet for dissipating heat from the power battery coolant; an engine fan correspondingly arranged at the engine radiator for assisting the engine radiator in heat dissipation; a battery fan correspondingly arranged at the battery radiator for assisting the battery radiator in heat dissipation.

5. The engine-battery thermal management system of claim 1, wherein, The heat exchange module is a heat exchanger having independent engine coolant channels and battery coolant channels for realizing the transfer of engine waste heat to the battery circuit without mixing the coolants.

6. A piecewise model predictive control method based on the engine-battery thermal management system of any one of claims 1-5, characterized in that, The method comprises the following steps: based on the physical characteristics of the heat management system, a system prediction model is established which can reflect the engine thermal dynamics, battery thermal dynamics and coupling relationship among multiple circuits; According to real-time temperature states of the engine and the battery, a segmented optimization objective function including an engine temperature target and a battery temperature target is set, wherein the optimization objective function can dynamically adjust optimization weights of the engine temperature target and the battery temperature target with changes in the temperature states; In each control cycle, the segmented optimization objective function is solved by rolling optimization based on the system prediction model and the current system state, to obtain an optimal control sequence of multiple actuators in a future time domain; The optimal control sequence is output to each actuator of the thermal management system to control distribution, circulation and heat dissipation of the coolant; In the next control cycle, the system state is updated and the rolling optimization solving and output process is repeated.

7. The piecewise model predictive control method of claim 6, wherein, The system prediction model is established, specifically including: Based on structural parameters and heat transfer characteristics of the thermal management system, a system prediction model taking engine coolant temperature and battery temperature as state variables is established, which can describe the dynamic influence of control input of each actuator on the system temperature state.

8. The piecewise model predictive control method of claim 6, wherein, The optimization weights are dynamically adjusted, specifically including: When the engine temperature is lower than a preset first temperature threshold, the weight of the engine temperature target in the optimization objective function is increased to preferentially ensure rapid warming of the engine; When the engine temperature reaches or exceeds the first temperature threshold and the battery temperature is lower than the target temperature, the weight of the battery temperature target in the optimization objective function is gradually increased to realize transfer of engine waste heat to the battery circuit.

9. The piecewise model predictive control method of claim 6, wherein, The rolling optimization solving is performed, specifically including: The rotation speed of the engine water pump, the rotation speed of the battery water pump, the opening of the engine control valve, the opening of the engine heat exchange valve, the opening of the engine heat dissipation valve, the opening of the battery heat dissipation valve, the power of the engine fan and the power of the battery fan are solved as decision variables for collaborative optimization, and the physical constraint range of each decision variable is considered in the solving process.

10. The piecewise model predictive control method of claim 6, wherein, The obtained optimal control sequence is used to make the opening control instructions of the engine control valve, the engine heat exchange valve, the engine heat dissipation valve and the battery heat dissipation valve present as control amounts that change continuously and smoothly over time.

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