Energy-saving control method for heating mode of electric vehicle and vehicle

Abstract

The application relates to an energy-saving control method for a heating mode of an electric vehicle and the vehicle, and the method comprises the following steps: judging whether the vehicle has a heating demand for an air conditioning system; when the vehicle has a heating demand for the air conditioning system, further judging whether a heat pump can operate; when the heat pump heating working condition is met, the heat pump operates; when the actual water temperature is less than or equal to the target water temperature minus 20 DEG C, the air conditioning system enters an over-adjusted heating stage; when the water temperature is greater than or equal to TW0+10 or the PTC operation time is greater than or equal to 20 min, the air conditioning system enters a transition stage; when the water temperature is less than or equal to TW0+0 and the PTC is less than or equal to 500 W or the water temperature is greater than or equal to TW0+12, the air conditioning system enters a general heating stage; and when the water temperature is less than or equal to TW0-20, the air conditioning system returns to the over-adjusted heating stage. When the heat pump and the PTC need to work simultaneously to meet the heating requirement, the heat pump always plays the maximum capacity, the PTC works through temperature, power and intervention conditions, the required heating quantity is obtained with the least power consumption, and the energy-saving purpose is achieved.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology and relates to an energy-saving control method and vehicle for heating mode of electric vehicles. Background Technology

[0002] For electric vehicles, driving range is a core competitive advantage for automakers and a top concern for consumers. The air conditioning system is the largest energy consumer besides the driving system, consuming the most energy in heating mode. Therefore, making the air conditioning system more energy-efficient is crucial for improving driving range. Currently, pure electric vehicle air conditioning systems mainly use a heat pump + PTC (Power Transmission Control) system for heating. When the ambient temperature is low, both the heat pump and PTC work simultaneously. As is well known, the efficiency of a PTC is less than 1, meaning that to provide the same amount of heat, the PTC consumes more energy than the heat pump. A key challenge is how to maximize the heat pump's capacity, with the PTC supplementing the shortfall, rather than having the PTC operate before the heat pump reaches its maximum capacity.

[0003] Patent document 1 (CN113479035A) discloses a compressor and PTC control method for a direct heat pump system in the field of electric vehicle heat pump air conditioning technology. The system includes a blower, an evaporator core, a heat pump core, a PTC heater, an evaporator temperature sensor, a driver's side temperature sensor, a passenger's side temperature sensor, an air conditioning unit, and a heat pump system compressor. The blower, evaporator core, heat pump core, and PTC heater are arranged sequentially along the airflow direction within the air conditioning unit. The evaporator temperature sensor is located within the air conditioning unit, between the evaporator core and the heat pump core. The target speed of the heat pump system compressor is controlled by the target outlet air temperature calculated using a comfort algorithm and the temperature feedback from the driver and passenger side temperature sensors. The PTC heater is controlled separately in two zones, left and right. The target outlet air temperature of the PTC heater is 1.5 degrees Celsius lower than the target outlet air temperature calculated by the comfort algorithm. Because the PTC responds quickly, this invention rapidly brings the system outlet air temperature close to the target outlet air temperature, thus meeting comfort requirements.

[0004] Patent document 2 (CN108859653B) discloses an electric vehicle air conditioning control method, characterized by comprising: real-time acquisition of the vehicle interior temperature; determining, when the air conditioning is first started, whether the difference between the vehicle interior temperature and the air conditioning set temperature exceeds a first preset temperature difference; if the difference between the vehicle interior temperature and the air conditioning set temperature exceeds the first preset temperature difference, simultaneously operating heat pump heating and PTC heating; reducing the PTC heating power as the difference between the vehicle interior temperature and the air conditioning set temperature decreases; and stopping PTC heating when the difference between the vehicle interior temperature and the air conditioning set temperature reaches a second preset temperature difference; PTC heating... The amount is automatically adjusted by the control system; the second preset temperature difference is less than the first preset temperature difference; after the difference between the vehicle interior temperature and the air conditioning set temperature reaches the second preset temperature difference, the method further includes: real-time acquisition of the outside temperature; determining whether the outside temperature is lower than the first preset temperature value; if the outside temperature is lower than the first preset temperature value, determining whether the outside temperature is lower than the second preset temperature value; the second preset temperature value is less than the first preset temperature value; if the outside temperature is not lower than the second preset temperature value, then simultaneously running heat pump heating and PTC heating; adjusting the PTC heating power as the difference between the vehicle interior temperature and the outside temperature changes.

[0005] Patent document 3 (CN112977004A) discloses a vehicle air conditioning heating control method, characterized in that the method includes: in response to the operation of turning on the vehicle air conditioning heating, determining the PTC target heating temperature of the vehicle air conditioning; controlling the PTC of the vehicle air conditioning to heat the air intake of the vehicle's passenger compartment according to the PTC target heating temperature; collecting the warm air temperature of the air intake in the vehicle's air conditioning pipeline in real time, and calculating the difference between the PTC target heating temperature and the warm air temperature; if the difference is less than the target difference, controlling the compressor of the vehicle air conditioning to heat the air intake of the vehicle's passenger compartment, wherein the target difference is determined based on the difference between the ambient temperature and the PTC target heating temperature; and controlling the PTC of the vehicle air conditioning to exit PTC heating when the warm air temperature reaches the PTC target heating temperature.

[0006] The aforementioned patents are not very relevant to this application. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the problems existing in the prior art and provide an energy-saving control method for electric vehicle heating mode.

[0008] This invention provides a control strategy for heat pumps and PTCs when using air conditioning for heating in electric vehicles. When both heat pumps and PTCs need to work simultaneously to meet heating requirements, the heat pump is controlled to always operate at its maximum capacity. The PTC is controlled to operate by adjusting temperature, power, and intervention conditions, so as to obtain the required heating capacity with minimal energy consumption and achieve energy saving.

[0009] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0010] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution:

[0011] An energy-saving control method for heating mode of an electric vehicle, characterized in that it includes:

[0012] Determine if the vehicle requires heating from the air conditioning system;

[0013] When the vehicle requires heating from the air conditioning system, further determine whether the heat pump can operate;

[0014] The heat pump operates when the conditions for heat pump heating are met.

[0015] When the actual water temperature is less than or equal to the target water temperature minus 20°C, the air conditioning system enters the overshoot heating stage;

[0016] When the water temperature is ≥ TWO+10 or the PTC running time is ≥ 20 minutes, the air conditioning system enters the transition phase.

[0017] When the water temperature is ≦TWO+0&PTC≦500W or the water temperature is ≧TWO+12, the air conditioning system enters the general heating stage.

[0018] When the water temperature is ≤ TWO-20, the air conditioning system returns to the overshoot heating stage.

[0019] Furthermore, to determine whether the vehicle requires heating from the air conditioning system, when the vehicle is in one of the following three states, it does not require heating from the air conditioning system, and the compressor and PTC are controlled independently:

[0020] The first method involves using a PTC heater separately when heating the battery.

[0021] The second scenario is that when battery cooling is required during heating, the air conditioning system switches to battery cooling operation and uses PTC for independent heating.

[0022] The third type is independent temperature control. Some seats are set to a low temperature and need cooling, while others are set to a high temperature and need heating. When this is the case, the air conditioning system switches to cooling mode and uses a PTC to ensure the required water temperature on the heating side.

[0023] Furthermore, when the vehicle requires heating from the air conditioning system, it is further determined whether the heat pump can operate. The heat pump cannot operate when one of the following three conditions is present:

[0024] The first scenario is when the heat pump system malfunctions or the compressor is under protection and the heat pump cannot work, in which case PTC heating is used separately.

[0025] The second option is to use PTC heating alone when the ambient temperature is below -20℃.

[0026] The third type involves using a separate PTC heater for the vehicle interior while charging.

[0027] Furthermore, the heat pump operates when the conditions for heat pump heating are met;

[0028] The ambient temperature suitable for heat pump heating is between 0 and -20℃.

[0029] Furthermore, during the overshoot heating stage: PTC target water temperature = TWO + 20, power is controlled according to the "PTC power upper limit control chart"; compressor target water temperature = TWO + 15; speed is automatically controlled.

[0030] Furthermore, during the transition phase: PTC target water temperature = TWO + 0, power is controlled according to the "PTC power upper limit control chart"; compressor target water temperature = TWO + 0; speed is locked at the upper limit speed.

[0031] Furthermore, in the first heating stage: PTC target water temperature = TWO-12, power is controlled according to the "PTC power upper limit control chart"; compressor target water temperature = TWO+0; speed is automatically controlled.

[0032] Furthermore, after entering the transition phase, the PTC is cut off, and the compressor locks its upper limit speed; when the water temperature drops below TWO, it triggers the entry into the normal heating phase.

[0033] Furthermore, when the indoor heat load is very small, and the water temperature starts to drop from TWO+10 but does not drop below TWO and remains at a certain value above TWO, a transition phase timer is added, and the allowable dwell time during the transition phase is set.

[0034] A vehicle characterized by employing the aforementioned control method.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] This invention addresses the need for simultaneous operation of a heat pump and a PTC to meet heating requirements. It controls the heat pump to always operate at maximum capacity and regulates the PTC's operation through temperature, power, and intervention conditions. This achieves the desired heating capacity with minimal energy consumption, thus saving energy. This invention enables the vehicle interior to achieve the same cooling effect as existing technologies while saving 9.5% of energy. Attached Figure Description

[0037] The invention will now be further described with reference to the accompanying drawings:

[0038] Figure 1 This is a logic block diagram of an energy-saving control method for electric vehicle heating mode according to the present invention;

[0039] Figure 2 PTC power upper limit control chart;

[0040] Figure 3a This is a diagram illustrating the value of TWO1;

[0041] Figure 3b This is a diagram illustrating the values ​​of TWO2;

[0042] Figure 4 A schematic diagram of the power consumption of existing PTC technology;

[0043] Figure 5 This is a schematic diagram of the PTC power consumption of the present invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this invention. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this invention, and should not be construed as limiting the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The embodiments of this invention will be described in detail below with reference to the accompanying drawings.

[0045] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0046] The present invention will now be described in detail with reference to the accompanying drawings:

[0047] This invention provides a control strategy for heat pumps and PTCs during air conditioning heating in electric vehicles, which can fully utilize the advantages of the two different heat sources, thereby reducing the energy consumption of the air conditioning system and increasing the driving range of the electric vehicle.

[0048] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] See Figure 1 , Figure 2 For each stage, the specific values ​​of the target water temperature of the PTC and compressor, the compressor speed, and the upper limit of the PTC power are detailed in Table 1 below:

[0050] Table 1

[0051]

[0052] *1. When the outside air temperature is >0℃, the PTC is prohibited from starting. At this time, the target water temperature of the compressor is changed to TWO.

[0053] *2. When the blower mode is DEF, in order to ensure the defrosting effect, the PTC target water temperature should be changed to TWO.

[0054] See Figure 1 Complete control logic (heat pump and PTC water heating work simultaneously);

[0055] The initial design of this logic is based on the scenario of simultaneous heating by a heat pump and a PTC. The goal is to raise the water temperature as quickly as possible initially, and then cut off the PTC as soon as the water temperature reaches a sufficiently high level, so as to keep the heat pump operating independently and achieve energy saving.

[0056] After Ig on, it determines whether the vehicle has a heating requirement for the air conditioning system. When the vehicle is in one of the following three states, it does not have a heating requirement for the air conditioning system, and the compressor / PTC is controlled independently.

[0057] 1. When heating the battery, use a PTC heater separately;

[0058] 2. During heating, when battery cooling is required, the air conditioning system switches to battery cooling mode and uses PTC for heating separately;

[0059] 3. Independent temperature control: When some seats are set to a low temperature and require cooling, while others are set to a high temperature and require heating, the air conditioning system switches to cooling mode and uses a PTC to ensure the required water temperature on the heating side.

[0060] After Ig on, when the vehicle has a heating requirement for the air conditioning system, further determine whether the heat pump can operate. The heat pump cannot work when the following conditions are met.

[0061] 1. If the heat pump system malfunctions or the compressor is under protection and the heat pump cannot work, use PTC for heating separately;

[0062] 2. When the ambient temperature is below -20℃, use PTC heating alone.

[0063] 3. During charging, the vehicle interior heating uses a separate PTC heater.

[0064] The heat pump operates when the conditions for heat pump heating are met (ambient temperature between 0 and -20℃).

[0065] When the actual water temperature is less than or equal to the target water temperature minus 20°C, the air conditioning system enters the overshoot heating stage. During this stage, the PTC target water temperature is TWO + 20°C, and the power is controlled according to the "PTC power upper limit control chart"; the compressor target water temperature is TWO + 15°C; and the speed is automatically controlled.

[0066] When the water temperature is ≥ TWO+10 or the PTC running time is ≥ 20 minutes, the air conditioning system enters the transition phase. During this phase, the PTC target water temperature is TWO+0, the power is controlled according to the "PTC power upper limit control chart", the compressor target water temperature is TWO+0, and the speed is locked at the upper limit speed.

[0067] When the water temperature is ≤TWO+0 and PTC is ≤500W, or when the water temperature is ≥TWO+12, the air conditioning system enters the first heating stage. In this stage, the target water temperature of PTC is TWO-12, and the power is controlled according to the "PTC Power Upper Limit Control Chart"; the target water temperature of the compressor is TWO+0; and the speed is automatically controlled.

[0068] When the water temperature is ≤ TWO-20, the air conditioning system will return to the overheating stage.

[0069] After entering the transition phase, the PTC is cut off, and the compressor locks into its maximum operating speed. According to test results, the water temperature will generally drop below TWO, triggering the entry into the normal heating phase.

[0070] See Figure 3a , Figure 3b Target water temperature calculation: TWO = Min(TWO upper limit, TWO1, TWO2); TWO1 and TWO2 are calculated as follows: Figure 3a , Figure 3b Values.

[0071] TWO indicates the target warm air water temperature; TW indicates the warm air water temperature; TAO indicates the target blow-out temperature.

[0072] However, in special circumstances, if the indoor heat load is very low, and the water temperature starts to drop from TWO+10 but doesn't fall below TWO, remaining at a certain value above TWO, it will be unable to exit the transition phase for a long time, resulting in higher compressor power consumption. The solution is to add a transition phase timer and set an allowable dwell time during the transition phase.

[0073] The beneficial technical effects are shown in Table 2:

[0074] Table 2

[0075]

[0076] As shown in Table 2, the present invention can achieve the same cooling effect in the vehicle interior as the prior art, saving 9.5% of energy.

[0077] A vehicle employs the aforementioned energy-saving control method for electric vehicle heating mode.

[0078] When a heat pump and a PTC need to work simultaneously to meet heating requirements, this invention controls the heat pump to always operate at its maximum capacity and controls the PTC's operation through temperature, power, and intervention conditions to obtain the required heating capacity with minimal energy consumption, thereby achieving energy saving.

[0079] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be included within the scope of protection of the present invention. Furthermore, all content not described in detail in this specification is prior art known to those skilled in the art.

Claims

1. An energy-saving control method for heating mode of an electric vehicle, characterized in that, include: Determine if the vehicle requires heating from the air conditioning system; When the vehicle requires heating from the air conditioning system, further determine whether the heat pump can operate; The heat pump operates when the conditions for heat pump heating are met. When the actual water temperature is less than or equal to the target water temperature minus 20°C, the air conditioning system enters the overshoot heating stage; When the water temperature is ≥ the target warm air water temperature TWO+10 or the PTC running time is ≥ 20 minutes, the air conditioning system enters the transition phase. When the water temperature is ≤ target heating water temperature TWO+0 & PTC ≤ 500W or the water temperature is ≥ target heating water temperature TWO+12, the air conditioning system enters the normal heating stage. When the water temperature is ≤ target warm air water temperature TWO-20, the air conditioning system returns to the overshoot heating stage.

2. The energy-saving control method for electric vehicle heating mode according to claim 1, characterized in that: To determine if a vehicle requires heating from its air conditioning system, the system will not require heating when the vehicle is in one of the following three states, and the compressor and PTC will be controlled independently: The first method involves using a PTC heater separately when heating the battery. The second scenario is that when battery cooling is required during heating, the air conditioning system switches to battery cooling operation and uses PTC for independent heating. The third type is independent temperature control. Some seats are set to a low temperature and need cooling, while others are set to a high temperature and need heating. When this is the case, the air conditioning system switches to cooling mode and uses a PTC to ensure the required water temperature on the heating side.

3. The energy-saving control method for electric vehicle heating mode according to claim 2, characterized in that: When a vehicle requires heating from its air conditioning system, it is necessary to further determine whether the heat pump can operate. The heat pump cannot work if any of the following three conditions are met: The first scenario is when the heat pump system malfunctions or the compressor is under protection and the heat pump cannot work, in which case PTC heating is used separately. The second option is to use PTC heating alone when the ambient temperature is below -20℃. The third type involves using a separate PTC heater for the vehicle interior while charging.

4. The energy-saving control method for electric vehicle heating mode according to claim 3, characterized in that: The heat pump operates when the conditions for heat pump heating are met. The ambient temperature suitable for heat pump heating is between 0 and -20℃.

5. The energy-saving control method for electric vehicle heating mode according to claim 4, characterized in that: Overshoot heating stage: PTC target water temperature = target warm air water temperature TWO + 20, power is controlled according to "PTC power upper limit control chart"; Compressor target water temperature = target heater water temperature TWO + 15; speed is automatically controlled.

6. The energy-saving control method for electric vehicle heating mode according to claim 5, characterized in that: Transition phase: PTC target water temperature = target heater water temperature TWO + 0, power is controlled according to the "PTC power upper limit control chart"; Compressor target water temperature = target heater water temperature TWO + 0; speed is locked at the upper limit speed.

7. The energy-saving control method for electric vehicle heating mode according to claim 6, characterized in that: During the general heating stage: PTC target water temperature = target warm air water temperature TWO-12, and power is controlled according to the "PTC power upper limit control chart"; Compressor target water temperature = target heater water temperature TWO + 0; speed is automatically controlled.

8. The energy-saving control method for electric vehicle heating mode according to claim 7, characterized in that: After entering the transition phase, the PTC is cut off, and the compressor operates at its maximum speed. When the water temperature drops below the target heater water temperature (TWO), it triggers the normal heating phase.

9. The energy-saving control method for electric vehicle heating mode according to claim 8, characterized in that: When the indoor heat load is very small, and the water temperature starts to drop from the target heating water temperature TWO+10, but does not drop below the target heating water temperature TWO, and always remains at a certain value above the target heating water temperature TWO, add a transition phase timer and set the allowable dwell time during the transition phase.

10. A vehicle, characterized in that: The control method described in any one of claims 1 to 9 is adopted.

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