Vehicle air-conditioning fuel-saving control method and system based on engine universal characteristics

Abstract

The present invention relates to a vehicle air - conditioning fuel - saving control method and system based on the engine universal characteristic. The control method includes the following steps: determining an excitation current correction coefficient according to the fuel consumption value of the engine universal characteristic; correcting the refrigeration excitation current of the compressor according to the excitation current correction coefficient; detecting whether the exit condition for correcting the refrigeration excitation current of the compressor is satisfied, and when the exit condition is satisfied, exiting the correction of the refrigeration excitation current of the compressor. In the present invention, by adopting the air - conditioning fuel - saving control scheme based on the engine universal characteristic, the refrigeration capacity of the compressor can be more reasonably and efficiently exerted, reducing fuel consumption while ensuring the basic refrigeration demand of the vehicle and enhancing the vehicle power feeling.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle air conditioner control, and relates to a fuel-saving control method and system for vehicle air conditioners based on the universal characteristics of an engine. Background Art

[0002] With the increasing requirements for vehicle energy conservation, whether from regulatory requirements or market competitiveness considerations, each vehicle manufacturer attaches great importance to the fuel consumption of its products; at the same time, basically everyone who can drive is aware that the fuel consumption when driving with the air conditioner on in summer is completely different from that when driving with the air conditioner off. For vehicle manufacturers, low fuel consumption is an embodiment of product competitiveness; for users, low fuel consumption is related to the vehicle use cost; for the natural environment, low fuel consumption means lower carbon emissions, and reducing fuel consumption has undoubtedly become one of the main directions of vehicle technology development. When the existing vehicle control logic controls the excitation current of the compressor for refrigeration, it does not consider the influence of the fuel efficiency range of the engine on the excitation current of the compressor for refrigeration, and there is still a situation of low fuel efficiency, and in some working conditions, it will also affect the vehicle power. Therefore, it is necessary to adjust the refrigeration load of the vehicle air conditioner to optimize the fuel efficiency. Summary of the Invention

[0003] Aiming at the deficiencies of the above-mentioned existing technologies, the technical problem to be solved by the present invention is: to provide a fuel-saving control method and system for vehicle air conditioners based on the universal characteristics of an engine.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A fuel-saving control method for vehicle air conditioners based on the universal characteristics of an engine, comprising the following steps:

[0006] S100. Determine an excitation current correction coefficient according to the fuel consumption value of the engine's universal characteristics;

[0007] S200. Correct the excitation current of the compressor for refrigeration according to the excitation current correction coefficient;

[0008] S300. Detect whether the exit condition for correcting the excitation current of the compressor for refrigeration is satisfied, and when the exit condition is satisfied, exit the S200 step.

[0009] Further, the S100 step includes the following sub-steps:

[0010] S110. Predetermine the relative efficiency of the engine and the excitation current correction coefficient;

[0011] S120. Determine the fuel consumption value of the engine's universal characteristics according to the real-time speed and real-time torque of the engine;

[0012] S130. Calculate the relative engine efficiency based on the fuel consumption value of the engine's universal characteristic and the pre-set fuel consumption calibration value.

[0013] S140. Determine the excitation current correction coefficient based on the relative engine efficiency.

[0014] The S200 step includes the following sub-steps:

[0015] S210. Take the product of the target value of the compression refrigeration excitation current calculated by the existing vehicle control logic and the excitation current correction coefficient as the corrected target value of the compression refrigeration excitation current.

[0016] S220. Adjust the compression refrigeration excitation current according to the corrected target value of the compression refrigeration excitation current.

[0017] Furthermore, the calculation formula for the relative engine efficiency is:

[0018] Ei = 100×(C1 - Fcom) / C1

[0019] where Ei represents the relative engine efficiency; Fcom represents the fuel consumption value of the engine's universal characteristic; C1 represents the fuel consumption calibration value.

[0020] Furthermore, the method for determining the excitation current correction coefficient based on the relative engine efficiency is:

[0021] Calibrate the excitation current correction coefficient values corresponding to each relative engine efficiency value in combination with actual vehicle tests to obtain an excitation current correction coefficient calibration table, and query the excitation current correction coefficient calibration table according to the relative engine efficiency to obtain the corresponding excitation current correction coefficient.

[0022] Furthermore, the S100 step further includes the following sub-steps:

[0023] S150. Detect the throttle pedal opening. When the throttle pedal opening is greater than the pre-set opening threshold, fix the value of the excitation current correction coefficient as the value of the large throttle correction coefficient pre-set.

[0024] Furthermore, before executing the S200 step, first execute the following steps:

[0025] S160. Detect the ambient pressure value. When the ambient pressure value is less than the pre-set ambient pressure threshold, execute the S170 step;

[0026] S170. Query the pre-calibrated ambient pressure correction coefficient calibration table according to the ambient pressure value to obtain the corresponding ambient pressure correction coefficient;

[0027] S180. Adjust the excitation current correction coefficient according to the ambient pressure correction coefficient. The formula is as follows:

[0028] K1' = K1 × K2 - K2 + 1

[0029] Wherein, K1' represents the adjusted excitation current correction coefficient; K1 represents the excitation current correction coefficient before adjustment; K2 represents the ambient pressure correction coefficient, and K2 is a positive number less than 1.

[0030] Further, the step S300 includes the following sub-steps:

[0031] S310. Detect the current vehicle condition. When the vehicle is in the parking idle condition or the driving idle condition, exit the step S200.

[0032] Further, the step S300 includes the following sub-steps:

[0033] S321. Detect whether the air conditioner operation time reaches the first time threshold. When the air conditioner operation time reaches the first time threshold, execute the step S322;

[0034] S322. Detect the in-vehicle temperature and calculate the difference between the in-vehicle temperature and the preset reference temperature. If the difference is greater than the preset temperature difference threshold, execute the step S323;

[0035] S323. Detect the duration for which the difference is greater than the temperature difference threshold. If the duration exceeds the preset second time threshold, exit the step S200.

[0036] An on-vehicle air conditioner fuel-saving control system based on the engine universal characteristics, comprising

[0037] A correction coefficient calculation unit for determining the excitation current correction coefficient according to the fuel consumption value of the engine universal characteristics;

[0038] An excitation current adjustment unit for taking the product of the target value of the compression mechanism refrigeration excitation current calculated by the existing vehicle control logic and the excitation current correction coefficient as the corrected target value of the compression mechanism refrigeration excitation current, and correcting the compression mechanism refrigeration excitation current according to the corrected target value of the compression mechanism refrigeration excitation current; and

[0039] An exit correction judgment unit for detecting whether the exit condition for correcting the compression mechanism refrigeration excitation current is satisfied, and when the exit condition is satisfied, stopping the excitation current adjustment unit from working.

[0040] Further, the correction coefficient calculation unit includes

[0041] An engine relative efficiency calculation module for setting the value of the fuel consumption calibration amount, and calculating the engine relative efficiency according to the fuel consumption value of the engine universal characteristics and the fuel consumption calibration amount;

[0042] The exciting current correction factor query module is used to store the exciting current correction factor calibration table, and query the exciting current correction factor calibration table according to the relative efficiency of the engine to obtain the corresponding exciting current correction factor;

[0043] The ambient pressure correction module is used to store the ambient pressure correction factor calibration table, query the ambient pressure correction factor calibration table according to the ambient pressure value to obtain the corresponding ambient pressure correction factor, and adjust the exciting current correction factor according to the ambient pressure correction factor; and

[0044] The full-throttle correction module is used to set the value of the full-throttle correction factor, and when the throttle pedal opening is greater than the preset opening threshold, use the value of the full-throttle correction factor as the value of the exciting current correction factor;

[0045] The described exit correction judgment unit includes

[0046] The idle condition judgment module is used to detect the vehicle condition. When the vehicle is in the parking idle condition or the driving idle condition, the exciting current adjustment unit is stopped; and

[0047] The refrigeration effect judgment module sets the values of the first time threshold, the reference temperature, the temperature difference threshold and the second time threshold, and when the air conditioner operation time reaches the first time threshold, detects the vehicle interior temperature and calculates the difference between the vehicle interior temperature and the reference temperature. If the difference is greater than the temperature difference threshold and the duration exceeds the second time threshold, the exciting current adjustment unit is stopped.

[0048] In the present invention, the exciting current correction factor is calculated based on the engine universal characteristic as the correction amount of the compressor exciting current, and the exciting current correction factor is further corrected based on the vehicle external pressure environment, and the final exciting current for controlling the compressor refrigeration is obtained at a certain control ratio, so as to reduce fuel consumption while ensuring the basic refrigeration demand of the vehicle and improve the vehicle power feeling. And considering the requirements of the engine under different working conditions, the compressor refrigeration exciting current is further reduced under the full-throttle condition, which can optimize the acceleration performance of the engine to a certain extent. Exiting the correction of the compressor refrigeration exciting current in the parking idle condition, the driving idle condition and when the vehicle refrigeration is insufficient can ensure the refrigeration effect of the vehicle. Brief Description of the Drawings

[0049] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0050] Figure 1 It is a flowchart of a preferred embodiment of the on-vehicle air conditioner fuel-saving control method based on the engine universal characteristic of the present invention.

[0051] Figure 2 It is the flow chart of step S100.

[0052] Figure 3 It is the universal characteristic map of the engine in a specific example.

[0053] Figure 4 It is the flow chart of step S300.

[0054] Figure 5 It is the structural block diagram of a preferred embodiment of the vehicle air - conditioner fuel - saving control system based on the engine universal characteristics of the present invention. Specific embodiments

[0055] The following uses specific specific examples to illustrate the implementation manners of the present invention. The diagrams provided in the following embodiments only schematically illustrate the basic concept of the present invention. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0056] As Figure 1 shown, a preferred embodiment of the vehicle air - conditioner fuel - saving control method based on the engine universal characteristics of the present invention includes the following steps:

[0057] S100. Determine the excitation current correction coefficient according to the fuel consumption value of the engine universal characteristics. As Figure 2 shown, this step may include the following sub - steps:

[0058] S110. Predetermine the engine relative efficiency and the excitation current correction coefficient. In this embodiment, the concept of the engine relative efficiency is introduced. The engine relative efficiency takes the fuel consumption performance of the engine bench universal characteristics as a reference, and distinguishes the high - efficiency area and the low - efficiency area of the engine operation through the engine relative efficiency. This efficiency value is a relative value, not an absolute value, and is one of the input signals for calculating the compression refrigeration excitation current in this embodiment; when the engine operates in the high - efficiency area, increase the compression refrigeration excitation current; when the engine operates in the low - efficiency area, reduce the compression refrigeration excitation current to achieve the effect of fuel saving.

[0059] S120. Determine the fuel consumption value of the engine universal characteristics according to the real - time speed and real - time torque of the engine, so as to calculate the engine relative efficiency according to the fuel consumption value of the engine universal characteristics. As Figure 3 shown, it is the universal characteristic map of the engine in a specific example.

[0060] S130. Calculate the engine relative efficiency according to the fuel consumption value of the engine universal characteristics and the fuel consumption calibration value. The fuel consumption calibration value is preset according to the universal characteristics of the engine. The calculation formula of the engine relative efficiency is:

[0061] Ei = 100×(C1 - Fcom) / C1

[0062] Where, Ei represents the relative efficiency of the engine; Fcom represents the fuel consumption value of the engine's universal characteristics; C1 represents the fuel consumption calibration value, which is generally determined according to the maximum fuel consumption point of the engine's universal characteristics. In this embodiment, the value of the fuel consumption calibration value C1 is set to be slightly greater than the maximum fuel consumption point of the engine's universal characteristics to ensure that the relative efficiency value in the low-efficiency region is near 0. For example, for Figure 3 a specific instance, the value of C1 can be set to 400 g / kwh. As shown in Table 1, it is the correspondence table of the real-time speed and real-time torque of the engine and the relative efficiency of the engine calculated according to Figure 3 the engine's universal characteristics.

[0063] Table 1

[0064]

[0065] The larger the relative efficiency value of the engine calculated using the above formula, the higher the efficiency of the engine at this speed and torque point and the lower the fuel consumption; therefore, when formulating the refrigeration control logic of the compressor, the air conditioner should be made to work in this high-efficiency interval as much as possible. In addition to meeting the driver's refrigeration requirements, sufficient cold air should be stored at the evaporator end to make up for the problem of insufficient refrigeration caused by the subsequent engine working in the low-efficiency region.

[0066] S140. Determine the excitation current correction coefficient K1 according to the relative efficiency Ei of the engine. The specific method is as follows:

[0067] Pre-calibrate the excitation current correction coefficient values corresponding to each engine relative efficiency value according to the engine performance indicators and the vehicle occupant compartment structure, combined with real vehicle tests, to obtain the excitation current correction coefficient calibration table; query the excitation current correction coefficient calibration table according to the engine relative efficiency to obtain the corresponding excitation current correction coefficient. As shown in Table 2, it is the excitation current correction coefficient calibration table calibrated in a specific instance.

[0068] Table 2

[0069]

[0070] As can be seen from Table 2, in this example, the relative engine efficiency Ei = 30 is used as the division criterion. When Ei < 30, it is considered that the engine is operating in the low-efficiency region. At this time, the excitation current correction coefficient K1 < 1 to reduce the excitation current of the compressor for refrigeration, and the minimum value of K1 can be 0.7. When Ei > 30, it is considered that the engine is operating in the high-efficiency region. At this time, the excitation current correction coefficient K1 > 1 to increase the excitation current of the compressor for refrigeration, and the maximum value of K1 can be 1.4. Of course, this is just an example here. In actual use, Table 2 can be divided more finely, or other values can be taken according to the actual vehicle test data of the engine.

[0071] In order to make the control logic of the on-vehicle air conditioner fuel-saving control method more flexible and improve the driving experience when the driver steps on the accelerator hard, the engine efficiency value or the correction coefficient can also be separately assigned under the large-throttle condition. At this time, the following steps can be executed:

[0072] S150. Detect the throttle pedal opening. When the throttle pedal opening is greater than the opening threshold, fix the value of the excitation current correction coefficient to the value of the large-throttle correction coefficient. The opening threshold and the value of the large-throttle correction coefficient are preset according to the engine performance indicators. For example, the opening threshold can be preset to 80%, and the value of the large-throttle correction coefficient can be preset to 0.5 (or smaller); when the throttle pedal opening is greater than 80%, the excitation current correction coefficient K1 is assigned the fixed value of 0.5 (or smaller). Thus, the power output of the engine can be fully guaranteed, and the driver's demand for power can be satisfied as much as possible. This is beneficial to improving the driving experience and overtaking safety, and the effect is significantly better than the control method of directly cutting off the air conditioner compressor when stepping on the accelerator hard.

[0073] When the driver steps on the accelerator hard, it indicates that the driver has a large torque demand. At this time, the engine is bound to operate in the large-load region, that is, in the relatively low-efficiency region, and the excitation current of the compressor for refrigeration needs to be reduced. In this embodiment, when in the large-throttle condition, the excitation current correction coefficient K1 is assigned a value smaller than the lowest value of K1 in the excitation current correction coefficient calibration table (in the above example, the value of the large-throttle correction coefficient is set to 0.5, which is significantly smaller than the lowest value of 0.7 in Table 2). This can enable the engine to transfer more power to the wheel end, which is beneficial to improving the vehicle's power performance.

[0074] In addition, considering the plateau environment, due to the relatively low atmospheric pressure, the load range of the engine operation is limited (especially for naturally aspirated engines). Moreover, due to the small pumping loss of the engine, the engine as a whole will operate in a smaller load range, and the high-efficiency range of the engine narrows. The excitation current correction coefficient needs to appropriately reduce the correction amplitude of the excitation current for the compressor refrigeration to avoid insufficient vehicle refrigeration in special cases. Therefore, to further correct the excitation current for the compressor refrigeration so that the above control logic is applicable to the plateau environment, the following steps can also be executed:

[0075] S160. Detect the ambient pressure value. When the ambient pressure value is less than the ambient pressure threshold, it is considered that the atmospheric pressure is relatively low, which may cause the load range of the engine operation to be limited, and then execute step S170. The ambient pressure threshold is preset according to the influence of the ambient pressure value on the engine performance.

[0076] S170. Query the ambient pressure correction coefficient calibration table according to the ambient pressure value to obtain the corresponding ambient pressure correction coefficient. The ambient pressure correction coefficient calibration table is obtained by calibrating the ambient pressure correction coefficient values corresponding to each ambient pressure value in advance in combination with vehicle tests.

[0077] S180. Adjust the excitation current correction coefficient obtained in step S140 or S150 according to the ambient pressure correction coefficient. The formula is as follows:

[0078] K1' = K1 × K2 - K2 + 1

[0079] Where, K1' represents the adjusted excitation current correction coefficient; K1 represents the excitation current correction coefficient obtained in step S140 or S150; K2 represents the ambient pressure correction coefficient, and K2 is a positive number less than 1.

[0080] For example, when the ambient pressure correction coefficient K2 = 0.5, assuming the excitation current correction coefficient K1 before adjustment is 1.4, then the adjusted excitation current correction coefficient K1' = 1.4 × 0.5 - 0.5 + 1 = 1.2.

[0081] Assuming the excitation current correction coefficient K1 before adjustment is 0.7, then the adjusted excitation current correction coefficient K1' = 0.7 × 0.5 - 0.5 + 1 = 0.85.

[0082] It can be seen that by introducing the ambient pressure correction coefficient K2, the value of the adjusted excitation current correction coefficient K1' can be closer to "1" compared with the excitation current correction coefficient K1 obtained in step S140, so as to reduce the correction amplitude of the excitation current for the compressor refrigeration and avoid the problem of insufficient refrigeration in the environment with relatively low atmospheric pressure.

[0083] S200. Correct the refrigeration excitation current of the compressor according to the excitation current correction factor. This step may include the following sub-steps:

[0084] S210. Multiply the target value of the refrigeration excitation current of the compressor calculated by the existing vehicle control logic by the excitation current correction factor (K1 when the ambient pressure value is not less than the ambient pressure threshold, and K1' when the ambient pressure value is less than the ambient pressure threshold) to obtain the corrected target value of the refrigeration excitation current of the compressor.

[0085] S220. Adjust the refrigeration excitation current of the compressor according to the corrected target value of the refrigeration excitation current of the compressor.

[0086] Combining step S100 and step S200 provides a control logic for correcting the refrigeration excitation current of the compressor based on the fuel consumption of the engine's universal characteristics, thereby reducing fuel consumption while ensuring the basic refrigeration requirements of the vehicle.

[0087] S300. Detect whether the exit condition for correcting the refrigeration excitation current of the compressor is met. When the exit condition is met, exit step S200. This step is mainly to exit the above control logic when the control logic of steps S100 to S200 is not applicable to avoid the problem of insufficient refrigeration. As Figure 4 shown, step S300 includes the following sub-steps:

[0088] S310. Detect the current vehicle condition. When the vehicle is in the parking idle condition or the driving idle condition, exit step S200, that is, exit the correction of the refrigeration excitation current of the compressor, and still use the existing vehicle control logic to control the excitation current of the compressor. When the engine is idling in place, the control logic of steps S100 to S200 cannot play its advantages, and since the engine is basically operating in a low-efficiency range and the working condition is fixed, insufficient refrigeration of the compressor may occur after correction using the above control logic. Therefore, it is necessary to exit the above control logic when the vehicle is in the parking idle and driving idle conditions to ensure the refrigeration effect of the vehicle.

[0089] To avoid the situation of insufficient refrigeration caused by unpredictable factors when using the control logic of steps S100 to S200, step S300 can also add a judgment on the insufficient refrigeration situation of the vehicle and exit the control of the excitation current of the compressor when the vehicle has insufficient refrigeration. It includes the following sub-steps:

[0090] S321. Detect whether the operating time of the air conditioner reaches the first time threshold. When the operating time of the air conditioner reaches the first time threshold, it indicates that the vehicle's refrigeration time is sufficient, and it is possible to determine whether there is insufficient refrigeration in the vehicle, and perform step S322. The first time threshold is preset to facilitate detection after the air conditioner compressor cools the passenger compartment sufficiently.

[0091] S322. Detect the temperature inside the vehicle and calculate the difference between the temperature inside the vehicle and the reference temperature. If the difference is greater than the preset temperature difference threshold, it indicates that there may be insufficient refrigeration in the vehicle, and perform step S323 for further judgment. The reference temperature is preset according to people's comfort requirements for the ambient temperature.

[0092] S323. To avoid misjudgment, it is possible to further detect the duration during which the difference is greater than the temperature difference threshold. If the duration is greater than the second time threshold, it can be determined that the vehicle indeed has insufficient refrigeration, exit step S200, and use the existing control logic of the vehicle to control the excitation current of the compressor to ensure the refrigeration effect of the vehicle. The second time threshold is preset to leave a time redundancy when judging whether there is insufficient refrigeration.

[0093] In this embodiment, the excitation current correction coefficient is calculated based on the engine universal characteristic as the correction amount of the compressor excitation current, and the excitation current correction coefficient is further corrected based on the vehicle external pressure environment, and the final excitation current for controlling the compressor refrigeration is obtained at a certain control ratio, so as to reduce fuel consumption while ensuring the basic refrigeration requirements of the vehicle and improve the vehicle power feeling. Considering the requirements of the engine under different working conditions, the compressor refrigeration excitation current is further reduced under the large throttle condition, which can optimize the acceleration performance of the engine to a certain extent. Exiting the correction of the compressor refrigeration excitation current in the parking idle condition, driving idle condition, and when the vehicle has insufficient refrigeration can ensure the refrigeration effect of the vehicle.

[0094] As Figure 5 shown, the present invention also discloses an on-vehicle air conditioner fuel-saving control system based on the engine universal characteristic. A preferred embodiment of the on-vehicle air conditioner fuel-saving control system based on the engine universal characteristic of the present invention includes a correction coefficient calculation unit, an excitation current adjustment unit, and an exit correction judgment unit.

[0095] The correction coefficient calculation unit is used to determine the excitation current correction coefficient according to the fuel consumption value of the engine universal characteristic. The correction coefficient calculation unit may include an engine relative efficiency calculation module, an excitation current correction coefficient query module, an environmental pressure correction module, and a large throttle correction module.

[0096] The engine relative efficiency calculation module is used to preset the value of the fuel consumption calibration quantity, and calculate the engine relative efficiency according to the fuel consumption value of the engine universal characteristic and the fuel consumption calibration quantity. The calculation formula of the engine relative efficiency is as follows:

[0097] Ei = 100×(C1 - Fcom) / C1

[0098] where Ei represents the engine relative efficiency; Fcom represents the fuel consumption value of the engine universal characteristic; C1 represents the fuel consumption calibration quantity, which is generally determined according to the maximum fuel consumption point of the engine universal characteristic.

[0099] The excitation current correction coefficient query module is used to store the excitation current correction coefficient calibration table, and query the excitation current correction coefficient calibration table according to the engine relative efficiency to obtain the corresponding excitation current correction coefficient K1. The excitation current correction coefficient calibration table can calibrate the excitation current correction coefficient values corresponding to each engine relative efficiency value according to the engine performance index and the vehicle occupant compartment structure, combined with the actual vehicle test, so as to achieve differential coverage for different engines and different vehicles.

[0100] The ambient pressure correction module is used to store the ambient pressure correction coefficient calibration table, query the ambient pressure correction coefficient calibration table according to the ambient pressure value to obtain the corresponding ambient pressure correction coefficient, and adjust the excitation current correction coefficient K1 according to the ambient pressure correction coefficient. This can avoid the problem that when the atmospheric pressure is low, the engine will operate in a smaller load range as a whole, the high-efficiency range of the engine will narrow, and the vehicle refrigeration will be insufficient.

[0101] The full-throttle correction module is used to preset the value of the full-throttle correction coefficient, and the value of the full-throttle correction coefficient is less than the lowest value of K1 in the excitation current correction coefficient calibration table. When the throttle pedal opening is greater than the preset opening threshold, the full-throttle correction module makes the excitation current correction coefficient query module stop working, and uses the value of the full-throttle correction coefficient as the value of the excitation current correction coefficient K1. When the driver steps on the full throttle, it means that the driver has a large torque demand, and the engine is bound to work in the high-load area. At this time, assigning the excitation current correction coefficient K1 a value smaller than the lowest value of K1 in the excitation current correction coefficient calibration table can enable the engine to transfer more power to the wheel end, which is beneficial to improving the vehicle power performance.

[0102] The excitation current adjustment unit is used to take the product of the compression refrigeration excitation current target value calculated by the existing vehicle control logic and the excitation current correction coefficient as the corrected compression refrigeration excitation current target value, and correct the compression refrigeration excitation current according to the corrected compression refrigeration excitation current target value.

[0103] The exit correction judgment unit is used to detect whether the exit condition for correcting the excitation current of the compression mechanism refrigeration is satisfied. When the exit condition is satisfied, the excitation current adjustment unit is stopped from working, so that the existing control logic of the vehicle is still used to control the excitation current of the compressor. The exit correction judgment unit may include an idle condition judgment module and a refrigeration effect judgment module.

[0104] The idle condition judgment module is used to detect the vehicle condition. When the vehicle is in the parked idle condition or the driving idle condition, the excitation current adjustment unit is stopped from working. When the engine is idling in place, the engine basically operates in a low-efficiency range and the working condition is fixed. Using the excitation current correction coefficient K1 to correct the excitation current of the compressor may result in insufficient refrigeration of the compression mechanism. When the vehicle is in the parked idle condition and the driving idle condition, the excitation current adjustment unit is stopped from working to exit the above control logic, and the existing control logic of the vehicle is still used to control the excitation current of the compressor, which can ensure the refrigeration effect of the vehicle.

[0105] The refrigeration effect judgment module is used to preset the values of the first time threshold, the reference temperature, the temperature difference threshold, and the second time threshold. When the air-conditioning operation time reaches the first time threshold, the refrigeration effect judgment module detects the temperature inside the vehicle and calculates the difference between the temperature inside the vehicle and the reference temperature. If the difference is greater than the temperature difference threshold and the duration exceeds the second time threshold, it is determined that the vehicle has insufficient refrigeration, and the excitation current adjustment unit is stopped from working, and the existing control logic of the vehicle is still used to control the excitation current of the compressor. By judging whether there is insufficient refrigeration in the vehicle, the situation of insufficient refrigeration of the vehicle caused by unpredictable factors can be avoided.

[0106] This embodiment adopts an air-conditioning fuel-saving control scheme based on the engine universal characteristics, which can more reasonably and efficiently exert the refrigeration capacity of the compressor, reduce fuel consumption while ensuring the basic refrigeration requirements of the vehicle, and at the same time can optimize the acceleration performance of the engine to a certain extent.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A vehicle air conditioner fuel-saving control method based on the engine universal characteristics, characterized in that, It includes the following steps: S100. Determine the excitation current correction coefficient according to the fuel consumption value of the engine's universal characteristics; S200. Correct the compression refrigeration excitation current according to the excitation current correction coefficient; S300. Detect whether the exit condition for correcting the compression refrigeration excitation current is satisfied. When the exit condition is satisfied, exit step S200; The S100 step includes the following sub-steps: S110. Predetermine the engine relative efficiency and the excitation current correction coefficient; S120. Determine the fuel consumption value of the engine's universal characteristics according to the real-time engine speed and real-time torque; S130. Calculate the engine relative efficiency according to the fuel consumption value of the engine's universal characteristics and the preset fuel consumption calibration value; S140. Determine the excitation current correction coefficient according to the engine relative efficiency; The S200 step includes the following sub-steps: S210. Take the product of the compression refrigeration excitation current target value calculated by the existing vehicle control logic and the excitation current correction coefficient as the corrected compression refrigeration excitation current target value; S220. Adjust the compression refrigeration excitation current according to the corrected compression refrigeration excitation current target value.

2. The on-vehicle air conditioner fuel-saving control method based on the engine universal characteristic according to claim 1, wherein The calculation formula of the engine relative efficiency is: Ei = 100×(C1 - Fcom) / C1 Where, Ei represents the engine relative efficiency; Fcom represents the fuel consumption value of the engine's universal characteristics; C1 represents the fuel consumption calibration value.

3. The on-vehicle air-conditioning fuel-saving control method based on the engine universal characteristics according to claim 1, wherein The method for determining the excitation current correction coefficient according to the engine relative efficiency is: Calibrate the excitation current correction coefficient values corresponding to each engine relative efficiency value in combination with real vehicle tests to obtain an excitation current correction coefficient calibration table, and query the excitation current correction coefficient calibration table according to the engine relative efficiency to obtain the corresponding excitation current correction coefficient.

4. The on-vehicle air conditioner fuel-saving control method based on the engine universal characteristic according to claim 1, characterized in that, The S100 step further includes the following sub-steps: S150. Detect the throttle pedal opening. When the throttle pedal opening is greater than the preset opening threshold, fix the value of the excitation current correction coefficient as the value of the large throttle correction coefficient preset.

5. The on-vehicle air conditioner fuel-saving control method based on the engine universal characteristic according to any one of claims 1 to 4, characterized in that, Before executing the S200 step, first execute the following steps: S160. Detect the ambient pressure value. When the ambient pressure value is less than the preset ambient pressure threshold, execute step S170; S170. Query the preset ambient pressure correction coefficient calibration table according to the ambient pressure value to obtain the corresponding ambient pressure correction coefficient; S180. Adjust the excitation current correction coefficient according to the ambient pressure correction coefficient. The formula is as follows: K1' = K1×K2 - K2 + 1 Where, K1' represents the adjusted excitation current correction coefficient; K1 represents the excitation current correction coefficient before adjustment; K2 represents the ambient pressure correction coefficient, and K2 is a positive number less than 1.

6. The on-vehicle air conditioner fuel-saving control method based on the engine universal characteristic according to claim 1, wherein The S300 step includes the following sub-steps: S310. Detect the current vehicle condition. When the vehicle is in the parking idle condition or the driving idle condition, exit step S200.

7. The on-vehicle air conditioner fuel-saving control method based on the engine universal characteristics according to claim 1, wherein The S300 step includes the following sub-steps: S321. Detect whether the air conditioner running time reaches the first time threshold. When the air conditioner running time reaches the first time threshold, execute step S322; S322. Detect the temperature inside the vehicle and calculate the difference between the temperature inside the vehicle and a preset reference temperature. If the difference is greater than a preset temperature difference threshold, execute step S323; S323. Detect the duration for which the difference is greater than the temperature difference threshold. If the duration exceeds a preset second time threshold, exit step S200.

8. An on-vehicle air conditioner fuel-saving control system based on the engine universal characteristics, characterized in that: including a correction coefficient calculation unit for determining an excitation current correction coefficient according to the fuel consumption value of the engine's universal characteristic; The method thereof includes the following sub-steps: S110. Predetermine the engine relative efficiency and the excitation current correction coefficient; S120. Determine the fuel consumption value of the engine's universal characteristic according to the real-time speed and real-time torque of the engine; S130. Calculate the engine relative efficiency according to the fuel consumption value of the engine's universal characteristic and a preset fuel consumption calibration value; S140. Determine the excitation current correction coefficient according to the engine relative efficiency; an excitation current adjustment unit for using the product of the target value of the compression refrigeration excitation current calculated by the existing vehicle control logic and the excitation current correction coefficient as the corrected target value of the compression refrigeration excitation current, and correcting the compression refrigeration excitation current according to the corrected target value of the compression refrigeration excitation current; and an exit correction judgment unit for detecting whether the exit condition for correcting the compression refrigeration excitation current is satisfied, and when the exit condition is satisfied, stopping the excitation current adjustment unit from working.

9. The on-vehicle air conditioner fuel-saving control system based on the engine universal characteristics according to claim 8, characterized in that: The correction coefficient calculation unit includes an engine relative efficiency calculation module for setting the value of the fuel consumption calibration value and calculating the engine relative efficiency according to the fuel consumption value of the engine's universal characteristic and the fuel consumption calibration value; an excitation current correction coefficient query module for storing an excitation current correction coefficient calibration table and querying the excitation current correction coefficient calibration table according to the engine relative efficiency to obtain the corresponding excitation current correction coefficient; an ambient pressure correction module for storing an ambient pressure correction coefficient calibration table, querying the ambient pressure correction coefficient calibration table according to the ambient pressure value to obtain the corresponding ambient pressure correction coefficient, and adjusting the excitation current correction coefficient according to the ambient pressure correction coefficient; and a wide-open throttle correction module for setting the value of the wide-open throttle correction coefficient and using the value of the wide-open throttle correction coefficient as the value of the excitation current correction coefficient when the throttle pedal opening is greater than a preset opening threshold; The exit correction judgment unit includes an idle condition judgment module for detecting the vehicle condition and stopping the excitation current adjustment unit from working when the vehicle is in the parking idle condition or the driving idle condition; and a refrigeration effect judgment module for setting the values of a first time threshold, a reference temperature, a temperature difference threshold and a second time threshold, and when the air conditioner operation time reaches the first time threshold, detecting the temperature inside the vehicle and calculating the difference between the temperature inside the vehicle and the reference temperature. If the difference is greater than the temperature difference threshold and the duration exceeds the second time threshold, stopping the excitation current adjustment unit from working.

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