A vehicle air conditioning heating energy consumption dynamic optimization method

Abstract

The present application relates to a kind of vehicle air conditioner heating energy consumption dynamic optimization method, specific steps include;According to the temperature demand of passenger in vehicle cabin at t time, obtain air conditioner heating demand x (t) in cabin, while obtaining cooling out water temperature y (t) in engine and the residual capacity z (t) of power battery, obtain engine waste heat Q w (t), and judge whether air conditioner heating demand x (t) exceeds engine waste heat Q w (t), if yes, then obtain the output power form expression P1 (t) of power battery and the energy supply power form expression P2 (t) of range extender after establishing balance relationship, subsequently establish objective function, calculate the output power real value of power battery and the energy supply power real value of range extender by algorithm program;If no, then heat is supplied to cabin by engine;Through the present application, optimal distribution can be directly found by using intelligent algorithm without relying on expert judgment.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicles, and more specifically, to a method for dynamically optimizing the heating energy consumption of vehicle air conditioning. Background Technology

[0002] Range-extended electric vehicles (REEVs) are electric vehicles that, based on pure electric vehicles, add a range extender to charge the battery or directly drive the motor to increase the driving range, thus overcoming the short driving range of pure electric vehicles. The power system of a REEV mainly consists of four parts: the battery, the drive system, the range extender, and the vehicle control system. The battery provides power to the drive system and also provides reverse drag current for the range extender's startup. The range extender typically consists of a small-displacement engine and a generator directly connected to it. The battery powers the engine in the range extender, and the range extender can charge the battery by rectifying the alternating current from the generator into direct current that matches the battery voltage. Compared to gasoline vehicles, REEVs consume a significant amount of energy when using air conditioning for heating in winter, accounting for approximately 20%-30% of the vehicle's total energy consumption, severely impacting the vehicle's driving range and battery life. How to save more energy while ensuring passenger compartment heating needs in low-temperature conditions has become a key focus and challenge in current research on the thermal management of REEVs.

[0003] Most current range-extended vehicles use a method where the power battery powers the vehicle heater (PTC) for heating. However, range-extended vehicles retain the engine in their power drive system (APU), allowing them to use the engine's waste heat to provide some heat to the passenger compartment. Furthermore, range-extended vehicles have two power sources to power the electrical components: the power battery and the range extender. In other words, the heater's energy source is provided by either the power battery or the range extender.

[0004] Currently, most range-extended vehicles still rely on the battery to directly power the heater for air conditioning heating. This mode causes frequent high-current charging and discharging of the battery, reducing its lifespan. A small number utilize waste heat from the engine and the range extender for coordinated power supply, but their control methods are mostly rule-based, with limited application of intelligent optimization algorithms. Furthermore, the rules they formulate rely too heavily on expert experience and cannot dynamically optimize. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and to provide a method for dynamic optimization of vehicle air conditioning heating energy consumption based on intelligent optimization.

[0006] The present invention provides a method for dynamically optimizing the heating energy consumption of vehicle air conditioning, the technical solution of which is as follows:

[0007] A method for dynamically optimizing the heating energy consumption of vehicle air conditioning includes the following steps:

[0008] Step 1: Based on the temperature requirements of passengers in the vehicle cabin at time t, obtain the air conditioning heating demand x(t) in the cabin, and at the same time obtain the coolant temperature y(t) in the engine at time t and the remaining power battery charge z(t) at time t.

[0009] Step 2: According to Joule's law, obtain the waste heat Q of the engine through the cooling water temperature y(t) in the engine. w (t), and determine whether the air conditioning heating demand x(t) exceeds the engine waste heat Q. w If so, then establish the air conditioning heating demand x(t) and the engine waste heat Q. w (t) and heater heating capacity Q P If the balance relationship of (t) is not found, proceed to step three; otherwise, adjust the cooling water outlet temperature y(t) to a value that matches the air conditioning heating demand x(t), and then supply heat to the passenger compartment through the engine, thus ending the process.

[0010] Step 3: Increase the heating capacity Q of the heater. P (t) is divided into the output power P1 of the power battery and the power supply power P2 of the range extender. Based on the remaining power capacity z(t) of the power battery, the output power of the power battery is represented in the form of P1(t) and the power supply power of the range extender is represented in the form of P2(t).

[0011] Step 4: Using the output power of the power battery in the form of P1(t), obtain the power battery electricity cost in the form of W1(t);

[0012] Step 5: Using the characteristic curve of the generator and the relationship between the power supplied by the range extender and the output power of the generator, obtain the fuel consumption power form Q of the engine. s (t), and then Q is expressed in the form of the engine's fuel consumption power. s (t) Obtain the fuel cost representation of the engine W2(t);

[0013] Step Six: Take the sum of the power battery electricity cost W1(t) and the engine fuel cost W2(t) as the objective function, and the power battery output power P1(t) as the decision variable. Use the algorithm to calculate the minimum value of the objective function, the true value of the power battery output power P1, and the true value of the range extender's power supply P2. Then, take the true value P1 as the power battery output power and the true value P2 as the range extender's power supply.

[0014] Compared with existing technologies, the method provided by this application offers at least the following advantages: By developing a coordinated working program for the engine, power battery, and range extender, this solution not only allows the power battery to directly supply energy to the heater but also utilizes waste heat from the engine and the range extender for coordinated energy supply. This reduces the likelihood of high-current charging and discharging of the power battery, thereby lowering its energy consumption and increasing its lifespan. Simultaneously, based on the remaining charge of the power battery, this solution establishes a representation of the power battery's output power (P1(t)) and the range extender's power supply (P2(t)). Based on these representations, an objective function is established, and an algorithm is used to calculate the true values ​​of the power battery's output power (P1) and the range extender's power supply (P2), thus achieving dynamic optimization of energy utilization without relying on expert experience.

[0015] Preferably, in step two, the waste heat Q of the engine is obtained by measuring the water temperature y(t) at the cooling water outlet of the engine. w The process of (t) includes the following steps:

[0016] Step 2.1: Obtain the inlet temperature y0 of the cooling water in the engine at time t;

[0017] Step 2.2: According to Joule's law, obtain the waste heat Q of the engine. w (t) is:

[0018] Q w (t)=C pw M w (y(t)-y0),

[0019] Among them, C pw M is the constant-pressure specific heat of the cooling water in the engine. w The mass flow rate of the cooling water in the engine;

[0020] By following the steps above, it can be easily determined whether the air conditioning heating demand x(t) exceeds the engine's waste heat Q. w (t), which in turn provides a convenient premise for the operation of the next item in step two.

[0021] Preferably, in step two, adjusting the cooling water temperature y(t) to a value that matches the air conditioning heating demand x(t), and then supplying heat to the passenger compartment through the engine, includes the following steps:

[0022] Step 2.3: Let the waste heat of the engine Q w (t) is equal to the air conditioning heating demand x(t), that is, let

[0023] Q w (t)=Cpw M w (y-y0)=x(t),

[0024] Solving the above equation inversely yields the value of y;

[0025] Step 2.4: Use the y value as the value that matches the air conditioning heating demand x(t), and then supply heat to the passenger compartment through the engine;

[0026] Once the coolant outlet temperature y(t) is adjusted to the value y, thus matching the air conditioning heating demand x(t), the air conditioning heating demand x(t) is equal to the residual heat when the coolant outlet temperature in the engine is y. This ensures that the air conditioning heating demand x(t) does not exceed the engine's residual heat Q. w (t) When the engine is preheated, heat is directly applied to the passenger compartment.

[0027] Preferably, step three includes the following steps:

[0028] Step 3.1: Using the balance relationship established in Step 2, the air conditioning heating demand x(t) and the engine waste heat Q are compared. w The difference between (t) and the heating capacity Q of the heater is taken as the heating capacity Q. P (t):

[0029] Step 3.2: Increase the heating capacity Q of the heater. P (t) is divided into the output power P1 of the power battery and the power supply power P2 of the range extender, that is, let

[0030] Q P (t) = P1 + P2;

[0031] Step 3.3: Formulate allocation rules based on the remaining electricity z(t), as follows:

[0032] When the remaining charge z(t) is less than the low charge threshold SOC of the power battery min At that time, the output power P1 of the power battery is less than zero;

[0033] When the power battery reaches a low charge threshold (SOC) min The remaining charge z(t) is less than or equal to the remaining charge z(t), and the remaining charge z(t) is less than or equal to the medium charge threshold (SOC) of the power battery. mid At that time, the power supply P2 of the range extender is less than or equal to the highest threshold value of the economic operating range of the range extender;

[0034] When the remaining energy z(t) is greater than the medium energy threshold SOC mid At that time, the power supply P2 of the range extender is zero;

[0035] Based on the aforementioned rules, the output power representation P1(t) of the power battery and the power supply representation P2(t) of the range extender are obtained.

[0036] This operation maximizes the use of waste heat from the range-extended vehicle engine and meets the heating needs of the passenger compartment.

[0037] Preferably, step five includes the following steps:

[0038] Step 5.1: Using the power generation efficiency η of the range extender and the power supply form of the range extender to express P2(t), obtain the output power P of the engine. eng (t), and using the characteristic curve of the engine, the fuel consumption rate b(t) of the engine is obtained, and the fuel consumption power form of the engine is obtained accordingly. s (t);

[0039] Step 5.2: Collect fuel price information and combine it with the fuel consumption power form to represent Q. s (t) yields the fuel cost representation W2(t);

[0040] This clearly establishes the fuel cost, providing a basis for establishing the objective function.

[0041] Preferably, the algorithm program in step six includes the ant colony algorithm program; since this algorithm program has good convergence and naturally depends on constraint conditions, it is easy to obtain the corresponding power. Attached Figure Description

[0042] Figure 1 This is a flowchart of the vehicle air conditioning heating energy consumption dynamic optimization method in this invention;

[0043] Figure 2 This is a flowchart of the ant colony algorithm in this invention. Detailed Implementation

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0045] Combination Figure 1 —2. This embodiment provides a method for dynamically optimizing the heating energy consumption of a vehicle air conditioning system, including the following steps:

[0046] Step 1: Based on the temperature requirements of passengers in the vehicle's passenger compartment at time t, obtain the air conditioning heating demand x(t) in the passenger compartment, and at the same time, obtain the coolant temperature y(t) in the engine and the remaining power battery charge z(t) at time t.

[0047] Specific data can be obtained through sensors or from information displayed in the vehicle.

[0048] Step 2: First, according to Joule's law, obtain the engine's waste heat Q from the engine's coolant outlet temperature y(t). w (t);

[0049] In this embodiment, this part includes the following steps:

[0050] Step 2.1: Obtain the engine coolant inlet temperature y0 at time t;

[0051] Step 2.2: According to Joule's law, obtain the engine waste heat Q. w (t) is:

[0052] Q w (t)=C pw M w (y(t)-y0),

[0053] Among them, C pw M is the constant-pressure specific heat of the cooling water in the engine. w The mass flow rate of cooling water in the engine is given.

[0054] Subsequently, it is determined whether the air conditioning heating demand x(t) exceeds the engine waste heat Q. w If so, then establish the air conditioning heating demand x(t) and the engine waste heat Q. w (t) and heater heating capacity Q P The equilibrium relationship of (t), that is, let

[0055] x(t)=Q w (t)+Q P (t),

[0056] Then proceed to step three;

[0057] If not, the cooling water temperature y(t) is adjusted to match the air conditioning heating demand x(t), and then the engine supplies heat to the passenger compartment, thus ending the process.

[0058] In this embodiment, the process of adjusting the cooling water temperature y(t) to match the air conditioning heating demand x(t) and then supplying heat to the passenger compartment through the engine includes the following steps:

[0059] Step 2.3, reduce the residual heat of the engine to Q w (t) is equal to the heating demand of the air conditioner x(t), that is, let

[0060] Q w (t)=C pw M w(y-y0)=x(t),

[0061] Solving the above equation in reverse yields a value for y that matches the air conditioning heating demand x(t);

[0062] Step 2.4: Use the value of y as the value that matches the heating demand x(t) of the air conditioner, that is, adjust the engine coolant outlet temperature to y, and then supply heat to the passenger compartment through the engine.

[0063] Step 3: Increase the heating capacity of the heater by Q. P (t) is divided into the output power P1 of the power battery and the power supply power P2 of the range extender. Based on the remaining power capacity z(t) of the power battery, the output power of the power battery is represented in the form of P1(t) and the power supply power of the range extender is represented in the form of P2(t).

[0064] In this embodiment, step three specifically includes the following steps:

[0065] Step 3.1: Using the balance relationship established in Step 2, combine the air conditioning heating demand x(t) with the engine waste heat Q. w The difference between (t) and the heating capacity Q of the heater is used as the heating capacity Q. P (t), that is, let

[0066] Q P (t)=x(t)-Q w (t)=x(t)-C pw M w y(t)-y0):

[0067] Step 3.2: Increase the heating capacity Q of the heater. P (t) is divided into the output power P1 of the power battery and the power supply power P2 of the range extender, that is, let

[0068] Q P (t) = P1 + P2;

[0069] Step 3.3: Formulate allocation rules based on the remaining electricity z(t), as follows:

[0070] When the remaining charge z(t) is less than the low charge threshold SOC of the power battery min At that time, the output power P1 of the power battery is less than zero;

[0071] When the power battery reaches a low charge threshold (SOC) min The remaining charge z(t) is less than or equal to the remaining charge z(t), and the remaining charge z(t) is less than or equal to the medium charge threshold (SOC) of the power battery. mid At that time, the range extender's power supply P2 is less than or equal to the maximum threshold value P of the range extender's economic operating range. 2max ;

[0072] When the remaining charge z(t) is greater than the medium charge threshold SOC mid At that time, the power supply P2 of the range extender is zero;

[0073] Based on this rule, the output power of the corresponding power battery is represented as P1(t) and the power supply of the corresponding range extender is represented as P2(t).

[0074] Step 4: Express P1(t) in the form of the power battery's output power, and obtain W1(t) in the form of the power battery's electricity cost. Specifically, for an electricity cost of R... e At that time, the power battery electricity cost, expressed in the form of W1(t), is the following variable upper limit integral:

[0075]

[0076] Step 5: Using the generator's characteristic curve and the relationship between the range extender's power supply and the generator's output power, obtain the engine's fuel consumption power form, Q. s (t), and then Q is expressed in the form of engine fuel consumption power. s W2(t) represents the fuel cost of the engine.

[0077] In this embodiment, step five includes the following steps:

[0078] Step 5.1: First, express P2(t) in terms of the range extender's power generation efficiency η and the range extender's power supply form to obtain the engine's output power P. eng (t), that is

[0079]

[0080] Subsequently, the engine's fuel consumption rate b(t) is obtained using the engine's characteristic curve, from which the engine's fuel consumption power form Q is derived. s (t). Specifically, based on the characteristic curve, the fuel consumption rate b(t) is obtained as:

[0081] b(t) = b(P) eng (t)),

[0082] Since the engine's waste heat provides some heating power, the actual engine output power should be reduced by the amount of waste heat, i.e., the engine's fuel consumption power is:

[0083]

[0084] Step 5.2: Collect fuel price information and express Q in the form of fuel consumption power. s(t) is represented as W2(t) in the form of fuel cost. Specifically, when the fuel price is R... f When the fuel cost is expressed in terms of W2(t), it is represented by the following variable upper limit integral:

[0085]

[0086] Step Six: Take the sum of the power battery electricity cost W1(t) and the engine fuel cost W2(t) as the objective function, and the power battery output power P1(t) as the decision variable. Use the algorithm program to calculate the minimum value of the objective function, as well as the true value of the power battery output power P1 and the true value of the range extender's power supply P2. Then, take the true value P1 as the power battery output power and the true value P2 as the range extender's power supply.

[0087] In this embodiment, the algorithm used in step six is ​​the ant colony algorithm. Specifically, the objective function is:

[0088] f(t) = W1(t) + W2(t).

[0089] Note that the power battery's charge level cannot exceed the maximum state of charge (SOC) of the power battery. max The output power of the power battery cannot exceed the maximum output power P of the power battery. 1max At the same time, the engine's waste heat must not exceed the maximum waste heat Q. wmax Therefore, the constraints are as follows:

[0090]

[0091] according to Figure 2 The program shown calculates the decision variable P1(t) and then obtains the optimal energy allocation.

[0092] Of course, the allocation rules in step 3.3 of this embodiment can be arranged as follows:

[0093] When SOC≤SOC min When P1(t) < 0, the battery is in a charging state and not discharging, and the range extender provides heating power and charges the battery.

[0094] When SOC min ≤SOC≤SOC mid When, if Q P (t)≤P Apuf1 When the power battery is charging and not discharging, the range extender provides heating power and charges the battery; if P Apuf1 ≤Q P ≤P Apuf2If Q is not charged or discharged, the power battery will not be charged or discharged, and the range extender will provide all the heating; P >P Apuf2 The range extender provides power P Apuf2 The remaining portion is supplied by the power battery;

[0095] When SOC≥SOC mid At that time, the heating power is entirely provided by the battery.

[0096] Among them, P Apuf1 P is the minimum threshold value for the economic operating range of the range extender. Apuf2 =P 2max This is the highest threshold value for the economic operating range of the range extender.

[0097] In summary, although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for dynamically optimizing the heating energy consumption of vehicle air conditioning, characterized in that: Includes the following steps: Step 1: Based on the temperature requirements of passengers in the vehicle cabin at time t, obtain the air conditioning heating demand x(t) in the cabin, and at the same time obtain the coolant temperature y(t) in the engine at time t and the remaining power battery charge z(t) at time t. Step 2: According to Joule's law, obtain the waste heat Q of the engine from the cooling water temperature y(t) in the engine. w (t), and determine whether the air conditioning heating demand x(t) exceeds the engine waste heat Q. w If so, then establish the air conditioning heating demand x(t) and the engine waste heat Q. w (t) and heater heating capacity Q P If the balance relationship of (t) is not found, proceed to step three; otherwise, adjust the cooling water outlet temperature y(t) to a value that matches the air conditioning heating demand x(t), and then supply heat to the passenger compartment through the engine, thus ending the process. Step 3: Increase the heating capacity Q of the heater. P (t) is divided into the output power P1 of the power battery and the power supply power P2 of the range extender. Based on the remaining power capacity z(t) of the power battery, the output power of the power battery is represented in the form of P1(t) and the power supply power of the range extender is represented in the form of P2(t). Step 4: Using the output power of the power battery in the form of P1(t), obtain the power battery electricity cost in the form of W1(t); Step 5: Using the generator's characteristic curve and the relationship between the range extender's power supply and the generator's output power, obtain the engine's fuel consumption power form, Q. s (t), and then Q is expressed in the form of the engine's fuel consumption power. s (t) Obtain the fuel cost representation of the engine W2(t); Step Six: Take the sum of the power battery electricity cost W1(t) and the engine fuel cost W2(t) as the objective function, and the power battery output power P1(t) as the decision variable. Use the algorithm to calculate the minimum value of the objective function, the true value of the power battery output power P1, and the true value of the range extender's power supply P2. Then, take the true value P1 as the power battery output power and the true value P2 as the range extender's power supply.

2. The method for dynamic optimization of vehicle air conditioning heating energy consumption according to claim 1, characterized in that: In step two, the waste heat Q of the engine is obtained by measuring the cooling water temperature y(t) at the outlet of the engine. w The process of (t) includes the following steps: Step 2.1: Obtain the cooling water inlet temperature y0 in the engine at time t; Step 2.2: According to Joule's law, obtain the waste heat Q of the engine. w (t) is: Q w (t)=C pw M w (y(t)-y0), Among them, C pw M is the constant-pressure specific heat of the cooling water in the engine. w The mass flow rate of cooling water in the engine is given.

3. The method for dynamic optimization of vehicle air conditioning heating energy consumption according to claim 2, characterized in that: In step two, adjusting the cooling water temperature y(t) to a value that matches the air conditioning heating demand x(t), and then supplying heat to the passenger compartment through the engine, includes the following steps: Step 2.3: Let the waste heat of the engine Q w (t) is equal to the air conditioning heating demand x(t), that is, let Q w (t)=C pw M w (y-y0)=x(t), The value of y can be obtained by solving the inverse equation above; Step 2.4: Use the y value as the value that matches the air conditioning heating demand x(t), and then supply heat to the passenger compartment through the engine.

4. The method for dynamic optimization of vehicle air conditioning heating energy consumption according to claim 3, characterized in that: Step three includes the following steps: Step 3.1: Using the balance relationship established in Step 2, the air conditioning heating demand x(t) and the engine waste heat Q are compared. w The difference between (t) and the heating capacity Q of the heater is taken as the heating capacity Q. P (t): Step 3.2: Increase the heating capacity Q of the heater. P (t) is divided into the output power P1 of the power battery and the power supply power P2 of the range extender, that is, let Q P (t)=P1+P2; Step 3.3: Formulate allocation rules based on the remaining electricity z(t), as follows: When the remaining charge z(t) is less than the low charge threshold SOC of the power battery min At that time, the output power P1 of the power battery is less than zero; When the power battery reaches a low charge threshold (SOC) min The remaining charge z(t) is less than or equal to the remaining charge z(t), and the remaining charge z(t) is less than or equal to the medium charge threshold (SOC) of the power battery. mid At that time, the power supply P2 of the range extender is less than or equal to the highest threshold value of the economic operating range of the range extender; When the remaining energy z(t) is greater than the medium energy threshold SOC mid At that time, the power supply P2 of the range extender is zero; Based on the aforementioned rules, the output power of the power battery, represented as P1(t), and the power supply of the range extender, represented as P2(t), are obtained.

5. The method for dynamic optimization of vehicle air conditioning heating energy consumption according to claim 4, characterized in that: Step five includes the following steps: Step 5.1: Using the power generation efficiency η of the range extender and the power supply form of the range extender to express P2(t), obtain the output power P of the engine. eng (t), and using the characteristic curve of the engine, the fuel consumption rate b(t) of the engine is obtained, and the fuel consumption power form of the engine is obtained accordingly. s (t); Step 5.2: Collect fuel price information and combine it with the fuel consumption power form to represent Q. s (t) yields the fuel cost representation W2(t).

6. The method for dynamic optimization of vehicle air conditioning heating energy consumption according to claim 5, characterized in that: The algorithm program in step six includes the ant colony algorithm program.

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