A control method and system for idle speed pressure stabilization of an air conditioning system

Abstract

The application provides a kind of air conditioning system idle speed pressure stable control method and system, belong to automobile air conditioning technical field, the method includes: with three section mode opens infinitely variable fan;Adjust the duty cycle of compressor until the duty cycle of compressor is 100%, complete air conditioning system idle speed pressure stable control.The three section mode is: pulse positioning-open loop drag-closed loop control.The mode of adjusting compressor is incremental, specific signal control is: field control receives control air conditioning opening signal, and is converted into pulse signal and is sent to compressor, after first time interval, field control sends incremental pulse signal to compressor again.The application considers whole vehicle thermal energy management system, through three section mode opens infinitely variable fan, adjusts the duty cycle of compressor, and front strategy, interval strategy and other methods, solves the problem that air conditioning system is frequently started and stopped at different ambient temperature, causes high vehicle energy consumption, poor cabin comfort.

Description

Technical Field

[0001] This invention belongs to the field of automotive air conditioning technology, and specifically relates to a control method and system for stabilizing the idling pressure of an air conditioning system. Background Technology

[0002] Currently, automakers are reducing manufacturing and production costs through platform planning and vigorous promotion of electrification, connectivity, intelligence, and sharing. The marginal definitions of various automotive component products are becoming increasingly sophisticated, while the requirements for air conditioning performance and comfort are also rising. Strategies are being implemented to control cooling capacity demand, thereby reducing overall vehicle energy consumption.

[0003] The product platform exhibits an issue where the air conditioning compressor fails to start cooling properly at idle. The cooling system utilizes a stepless fan; after the compressor is started, the fan operates with a 3-5 second delay, causing the system pressure to rise to the design protection pressure of 3.2 MPa. This triggers the compressor's high-pressure protection, preventing it from starting and cooling. The compressor only restarts once the system operating pressure drops below the protection pressure, severely impacting passenger cabin comfort.

[0004] Existing technology discloses a vehicle idling air conditioning control method and control system. This method sets three unconnected threshold intervals for the air conditioning pipe pressure, with the second threshold interval located between the high end of the first threshold interval and the low end of the third threshold interval. When the vehicle is idling, the air conditioning system control switch is activated, and the air conditioning pipe pressure is collected. When the initial pressure of the air conditioning pipe is between the low end of the first threshold interval and the high end of the second threshold interval, the air conditioning compressor is controlled to operate, while the fan is not operated. As the operating pressure of the air conditioning pipe increases from low to high, the fan starts operating when it reaches the high end of the second threshold interval; conversely, if the operating pressure decreases from high to low, the fan stops operating when it reaches the low end of the second threshold interval. It is evident that this invention controls the fan operation by adjusting the pipe pressure, and collecting the air conditioning pipe pressure requires an additional detection device, resulting in high control costs.

[0005] Based on this, the present invention provides a method and system for controlling the stabilization of idling pressure in an air conditioning system. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method and system for controlling the stabilization of idling pressure in an air conditioning system. Considering the vehicle's thermal management system, this invention solves the problem of high vehicle energy consumption and poor cabin comfort caused by frequent start-stop of the air conditioning system at different ambient temperatures by using a three-stage method to activate the stepless fan, adjusting the compressor duty cycle, and employing a pre-positioning strategy (the pressure when the air conditioning is on corresponds to the pressure when the fan is cooling down) and an interval strategy.

[0007] The first objective of this invention is to provide a method for controlling the stabilization of idle pressure in an air conditioning system, the method comprising:

[0008] The stepless fan is turned on in three stages;

[0009] Adjust the compressor's duty cycle until it reaches 100%, thus stabilizing the air conditioning system's idle pressure.

[0010] Furthermore, the three-stage method is: pulse positioning—open-loop drag—closed-loop control.

[0011] Furthermore, the compressor adjustment is performed incrementally, specifically via signal control as follows:

[0012] The domain controller receives the signal to turn on the air conditioner and converts it into a pulse signal, which is then sent to the compressor. After the first time interval, the domain controller sends an incrementing pulse signal to the compressor.

[0013] Furthermore, it also includes setting the pressure when the air conditioner is turned on to correspond to the pressure when the fan is dissipating heat.

[0014] Furthermore, it also includes: the stepless fan operates after the second time interval when the engine starts, and the compressor re-engages after the third time interval.

[0015] The second objective of this invention is to provide a control system for stabilizing the idling pressure of an air conditioning system, the system comprising: an activation module and an adjustment module;

[0016] The activation module is used to activate the stepless fan in a three-stage manner;

[0017] The adjustment module is used to adjust the compressor's duty cycle until the compressor's duty cycle is 100%, thereby achieving stable control of the air conditioning system's idle pressure.

[0018] Furthermore, the three-stage method is: pulse positioning—open-loop drag—closed-loop control.

[0019] Furthermore, the compressor adjustment is performed incrementally, specifically via signal control as follows:

[0020] The domain controller receives the signal to turn on the air conditioner and converts it into a pulse signal, which is then sent to the compressor. After the first time interval, the domain controller sends an incrementing pulse signal to the compressor.

[0021] Furthermore, the activation module is also used to set the delay time for the stepless fan to receive signals.

[0022] Furthermore, the activation module is also used to activate the stepless fan after the engine starts for a second time interval, and to re-engage the compressor after a third time interval.

[0023] The beneficial effects of this invention are:

[0024] This invention optimizes the start-up speed of the stepless fan by using a three-stage start-up method, allowing the air conditioning pressure to stabilize as quickly as possible. Compared to the traditional start-up method of stepless fans, it results in a greater starting torque for the motor, which can overcome external resistance.

[0025] By adjusting the compressor duty cycle and gradually increasing its occupancy until it reaches 100%, the compressor's start-up time is optimized, allowing the air conditioning pressure to stabilize as quickly as possible.

[0026] By matching the pressure when the air conditioner is turned on with the pressure when the fan is cooling, the delay time for the fan to receive signals can be reduced; and after the compressor protection trips due to high system pressure, the stepless fan can continue to work normally, which can reduce the system pressure, allowing the compressor to engage again, and the air conditioning system will return to normal, maintaining stable air conditioning pressure.

[0027] By using an interval strategy, the time required for the stepless fan to find its phase and increase its speed can be compensated, which facilitates the rapid stabilization of the air conditioning system pressure.

[0028] This invention does not require an additional detection device, and the control method is relatively simple.

[0029] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A flowchart of a control method for stabilizing the idling pressure of an air conditioning system according to an embodiment of the present invention is shown;

[0032] Figure 2 A graph showing the relationship between compressor duty cycle and current according to an embodiment of the present invention is shown;

[0033] Figure 3 A framework diagram of a control flow for stabilizing the idle pressure of an air conditioning system according to an embodiment of the present invention is shown.

[0034] In the diagram: 1. Enable module; 2. Adjust module. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] like Figure 1 As shown, an embodiment of the present invention provides a method for controlling the stabilization of idle pressure in an air conditioning system, comprising:

[0037] Step S1: Turn on the stepless fan in three stages;

[0038] Step S2: Adjust the compressor duty cycle until the compressor duty cycle is 100% to complete the control of the air conditioning system idle pressure stability.

[0039] Specifically, in step S1, the three-stage method is: positioning (pulse positioning to obtain the initial position) - open-loop drag (driving the motor at a fixed acceleration) - closed-loop control (after the pulse positioning is completed, dragging with a variable acceleration, the acceleration gradually increases, and the acceleration is slower in the initial stage to ensure that the motor follows synchronously).

[0040] Turning on the stepless fan in the above three ways can optimize the fan's start-up speed (reducing the time by about 3 seconds), allowing the air conditioning pressure to stabilize as quickly as possible.

[0041] Traditional stepless fan start-up method: It uses a fixed open-loop acceleration to quickly drive the fan at 220r / min. However, due to external factors, such as fan jamming or mud and water blockage causing increased rotor resistance and rotational inertia, the rotor cannot quickly follow the rotating magnetic field due to the given fast acceleration, resulting in chaotic motor torque and entering the stepless / stall protection. The characteristics of the above three-stage method: When starting, a smaller speed is given to drive the fan first, ensuring that the rotor is synchronized with the rotating magnetic field at all times, so that the motor torque is always positive, resulting in a larger motor starting torque, which can overcome the resistance caused by the external factors. The final effect is that the stepless fan starts up faster.

[0042] In step S1, the compressor is adjusted incrementally, and the specific signal control is as follows:

[0043] The domain controller receives the signal to turn on the air conditioner and converts it into a pulse signal, which is then sent to the compressor. After a first time interval, the domain controller sends an incrementing pulse signal to the compressor. The first time interval is set to 3 seconds. This embodiment of the invention only provides an example of the optimal solution for the first time interval; the specific value of the first time interval can also be any one of 1s, 1.2s, 1.4s, 1.6s, 2s, 2.2s, 2.4s, or 2.6s.

[0044] The above signal control is to achieve the control of stable idling pressure of the air conditioning system by gradually increasing the duty cycle after the compressor starts up, until the compressor's duty cycle reaches 100% after the first time interval.

[0045] In this embodiment of the invention, the duty cycle is exemplarily increased by 7% per second. This means that after the compressor starts, the duty cycle is increased by 7% per second after 3 seconds until the compressor's duty cycle reaches 100%, thus achieving stable idling pressure control of the air conditioning system. The initial displacement and duty cycle after the compressor starts are 30% (the initial duty cycle setting of a typical compressor), ultimately optimizing the compressor's start-up time (reducing the time by about 3 seconds) and stabilizing the air conditioning pressure as quickly as possible.

[0046] Specifically, the relationship between the compressor duty cycle and the current is as follows: Figure 2 As shown, Figure 2 In the diagram, the horizontal axis represents the duty cycle, and the vertical axis represents the duty cycle. 。

[0047] In some other embodiments of the present invention, the method for controlling the stabilization of the idling pressure of the air conditioning system further includes: setting the pressure when the air conditioner is turned on to correspond to the pressure when the fan is dissipating heat (i.e., the pre-positioning strategy) (at which time the pressure is 1.3 to 1.7 MPa);

[0048] This strategy can reduce the delay time when the fan receives signals (by approximately 1 second).

[0049] The aforementioned pre-emptive strategy allows the stepless fan to continue operating after the compressor protection trips due to high system pressure. This reduces system pressure, allowing the compressor to engage again and the air conditioning system to return to normal, thus maintaining stable air conditioning pressure.

[0050] In some other embodiments of the present invention, the method for controlling the stabilization of the idling pressure of the air conditioning system further includes: the stepless fan operates after a second time interval of engine start-up, and the compressor re-engages after a third time interval (interval strategy).

[0051] Wherein, the second time interval is 5s, which is the stable working time of the stepless fan after the engine starts. Therefore, the second time interval of 5s is only the characteristic time of the air conditioning system starting in this embodiment. Depending on the specific air conditioning system, the stable working time of the stepless fan after the engine starts is also different, and it can be flexibly set according to different air conditioning systems.

[0052] The third time interval is 4s. The second time interval of 4s is the optimal third time interval of the air conditioning system in this embodiment of the invention. The third time interval can also be any one of 3.1s, 3.2s, 3.4s, 3.6s, 3.8s, and 3.9s.

[0053] In this embodiment of the invention, the third time interval is set to 4 seconds in order to compensate for the time required for the stepless fan to start up (i.e., three-phase AC current is passed through the three-phase windings of the stator of the brushless DC motor to form a composite rotating magnetic field, which drives the rotor to run synchronously) and increase the speed, so as to facilitate the air conditioning system pressure to stabilize as soon as possible.

[0054] In some embodiments of the present invention, a control system for stabilizing the idling pressure of an air conditioning system is provided, comprising: an activation module 1 and an adjustment module 2;

[0055] The activation module 1 is used to activate the stepless fan in a three-stage manner;

[0056] The adjustment module 2 is used to adjust the duty cycle of the compressor until the duty cycle of the compressor is 100%, thereby completing the control of the idling pressure stability of the air conditioning system.

[0057] In some other embodiments of the present invention, the activation module is also used to set the delay time for the stepless fan to receive signals.

[0058] In other embodiments of the present invention, the activation module is also used to operate the stepless fan after the engine starts for a second time interval, and to engage the compressor again after a third time interval.

[0059] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the stabilization of idle pressure in an air conditioning system, characterized in that, The stepless fan is turned on in three stages; Adjust the compressor's duty cycle until it reaches 100%, thus achieving stable idling pressure control of the air conditioning system. The three-stage method is: pulse positioning - open-loop dragging - closed-loop control; The compressor adjustment method is incremental, and the specific signal control is as follows: The domain controller receives the signal to turn on the air conditioner and converts it into a pulse signal, which is then sent to the compressor. After the first time interval, the domain controller sends an incrementing pulse signal to the compressor.

2. The method for controlling the stabilization of idle pressure in an air conditioning system according to claim 1, characterized in that, Also includes: Set the pressure when the air conditioner is turned on to correspond to the pressure when the fan is dissipating heat.

3. A method for controlling the stabilization of idle pressure in an air conditioning system according to any one of claims 1-2, characterized in that, Also includes: The stepless fan starts working after the second time interval following engine startup, and the compressor engages again after the third time interval.

4. A control system for stabilizing the idle pressure of an air conditioning system, characterized in that, include: Enable and adjust modules; The activation module is used to activate the stepless fan in a three-stage manner; The adjustment module is used to adjust the duty cycle of the compressor until the duty cycle of the compressor is 100%, thereby achieving stable control of the idling pressure of the air conditioning system. The three-stage method is: pulse positioning - open-loop dragging - closed-loop control; The compressor adjustment method is incremental, and the specific signal control is as follows: The domain controller receives the signal to turn on the air conditioner and converts it into a pulse signal, which is then sent to the compressor. After the first time interval, the domain controller sends an incrementing pulse signal to the compressor.

5. A control system for stabilizing idle pressure in an air conditioning system according to claim 4, characterized in that, The activation module is also used to set the delay time for the stepless fan to receive signals.

6. A control system for stabilizing idle pressure in an air conditioning system according to any one of claims 4-5, characterized in that, The activation module is also used to activate the stepless fan after the second time interval of engine startup, and to re-engage the compressor after the third time interval.

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