Cooling water pump control method and system and vehicle

Abstract

The invention discloses a cooling water pump control method and system and a vehicle, and the method is characterized in that the method comprises the steps: obtaining a first control signal; acquiring a second control signal; according to the state of the second control signal, different control strategies are selected to control the rotating speed of the cooling water pump; when the second control signal is in the open state, the rotating speed of the cooling water pump is determined according to the duty ratio of the first control signal according to the first preset mapping relation; when the second control signal is in the closed state, the rotating speed of the cooling water pump is determined according to the duty ratio of the first control signal according to a second preset mapping relation; wherein in the second mapping relation and the second preset mapping relation, when the duty ratio of the first control signal is in the invalid interval, the cooling water pump is controlled to stop running. Through joint control of the first control signal and the second control signal, energy-saving control over the water pump is achieved, power output of an engine is guaranteed, fuel economy is improved, and the service life of parts is prolonged.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and in particular to a cooling water pump control method, a cooling water pump control system, and a vehicle. Background Technology

[0002] With the increasing sophistication of automotive functions and the widespread application of new energy vehicles, vehicle cooling systems are gradually developing towards intelligence, and intelligent cooling water pumps used for cooling engines and related components are being widely used.

[0003] In existing pulse width modulation (PWM) type coolant pump control systems, when a short circuit, open circuit, or poor contact occurs in the signal transmission line between the engine control unit (ECU) and the coolant pump controller, the coolant pump controller will receive an invalid duty cycle signal. The water pump controller will then drive the coolant pump to operate at maximum speed for an extended period of time. If the water pump operates at high speed for a long time, it will cause the vehicle battery to deplete and also generate significant noise. Summary of the Invention

[0004] This invention proposes a cooling water pump control method, system, and vehicle to solve the problem in related technologies where the cooling water pump controller runs the water pump at high speed for a long time when it receives an invalid duty cycle, resulting in the vehicle battery being depleted.

[0005] A first aspect of the present invention provides a cooling water pump control method, comprising: acquiring a first control signal; acquiring a second control signal; selecting different control strategies to control the speed of the cooling water pump according to the state of the second control signal; when the second control signal is in an on state, determining the speed of the cooling water pump by the duty cycle of the first control signal according to a first preset mapping relationship; when the second control signal is in a off state, determining the speed of the cooling water pump by the duty cycle of the first control signal according to a second preset mapping relationship; wherein, in the second preset mapping relationship, when the duty cycle of the first control signal is in an invalid range, controlling the cooling water pump to stop operating.

[0006] According to the above-mentioned technical means, the embodiments of the present invention set up joint control of the first control signal and the second control signal, and select different duty cycle and speed mapping relationships for different second control signal states, thereby ensuring engine cooling safety, avoiding long-term high-speed operation of the cooling water pump under invalid duty cycle conditions, reducing the risk of battery depletion and improving the overall vehicle noise performance.

[0007] In some implementations, in the first preset mapping relationship, when the duty cycle of the first control signal is in the linear adjustment range, the speed of the cooling water pump is linearly related to the duty cycle; when the duty cycle is greater than or equal to the maximum speed threshold, the cooling water pump is controlled to run at the maximum speed to meet the cooling requirements of the engine under high load conditions.

[0008] In some implementations, in the second preset mapping relationship, when the duty cycle of the first control signal is in the effective range, the cooling water pump is controlled to operate at the corresponding speed according to the duty cycle; when the duty cycle of the first control signal is in the first invalid range and the second invalid range, the cooling water pump is controlled to stop operating. By mapping the duty cycle in the invalid range to the stop state of the cooling water pump under the second preset mapping relationship, the cooling water pump is prevented from being mistakenly driven to the maximum speed when it is not needed or when there are abnormal operating conditions such as wiring harness failure.

[0009] In some implementations, the first invalid interval can be defined as a duty cycle less than or equal to a first threshold, the second invalid interval can be defined as a duty cycle greater than or equal to a second threshold, and the valid interval is between the first threshold and the second threshold.

[0010] In a further embodiment, in the second preset mapping relationship, when the duty cycle of the first control signal is within the effective range between the first threshold and the second threshold, the speed of the cooling water pump is linearly related to the duty cycle; when the duty cycle is less than or equal to the first threshold, or greater than or equal to the second threshold, the cooling water pump is controlled to stop operating. Through the above settings, when the cooling water pump needs to be operated, linear and fine adjustment of the cooling water pump speed can be achieved within the effective duty cycle range, while the pump operation can be completely stopped within the ineffective duty cycle range.

[0011] The aforementioned cooling water pump control method, through the joint control of a first control signal and a second control signal, enables the cooling water pump controller 1 to switch different speed control strategies according to the vehicle's ignition status, achieving differentiated control between ignition on and off conditions, thus improving the intelligence level of the control system. In the state where the second control signal is off, the pump stops via an invalid interval to prevent battery depletion. A first and second invalid interval are introduced into the second preset mapping relationship, and it is stipulated that the cooling water pump stops operating when the duty cycle of the first control signal falls into the invalid interval. This avoids the problem of the pump continuing to run at maximum speed for extended periods when Key OFF or signal line faults occur, effectively preventing battery depletion and reducing noise. A linear range and a maximum speed threshold are used to balance fine adjustment and extreme cooling capacity. A linear adjustment range and a maximum speed threshold are set in the first preset mapping relationship, allowing the cooling water pump to achieve linear adjustment within the normal operating range and quickly switch to maximum speed operation under high engine load or high temperature conditions, balancing energy saving and safety. The duty cycle range is divided by a threshold, resulting in a simple and easy-to-implement logic. The duty cycle of the first control signal is divided into a first invalid interval, an effective interval, and a second invalid interval by using a first threshold and a second threshold. The duty cycle interval determination can be achieved by a simple comparison operation, which has low computational load, low implementation cost, and is easy to deploy on existing controllers.

[0012] Another aspect of the present invention provides a cooling water pump control system for implementing any of the above methods. The system includes: a main controller for issuing a first control signal and a second control signal; a control unit for receiving the first control signal and the second control signal, selecting to invoke a first preset mapping relationship or a second preset mapping relationship based on the state of the second control signal, and generating a control command for controlling the speed of the cooling water pump based on the selected mapping relationship and the duty cycle of the first control signal.

[0013] In some implementations, selecting a mapping relationship and generating control commands based on the state of the second control signal specifically includes: when the second control signal is in an on state, determining the speed of the cooling water pump based on the duty cycle of the first control signal according to a first preset mapping relationship; when the second control signal is in a off state, determining the speed of the cooling water pump based on the duty cycle of the first control signal according to a second preset mapping relationship; wherein, in the second preset mapping relationship, when the duty cycle of the first control signal is in an invalid range, controlling the cooling water pump to stop operating.

[0014] In some implementations, in the first preset mapping relationship, when the duty cycle of the first control signal is in the linear adjustment range, the speed of the cooling water pump is linearly related to the duty cycle; when the duty cycle is greater than or equal to the maximum speed threshold, the cooling water pump is controlled to run at the maximum speed.

[0015] In some implementations, in the second preset mapping relationship, when the duty cycle of the first control signal is in the effective range, the cooling water pump is controlled to run at the corresponding speed according to the duty cycle; when the duty cycle of the first control signal is in the second invalid range, the cooling water pump is controlled to stop running.

[0016] The present invention provides a vehicle comprising the cooling water pump control system described in any of the preceding claims. Attached Figure Description

[0017] Figure 1 This is a wiring diagram illustrating the PWM cooling water pump control principle in existing technology. Figure 2 This is a schematic diagram of the relationship between the duty cycle and rotational speed of a cooling water pump according to a preset first mapping relationship in an embodiment of the present invention. Figure 3 This is a wiring diagram illustrating the control principle of the cooling water pump after adding a second control signal in an embodiment of the present invention. Figure 4 This is a schematic diagram of the relationship between the duty cycle and rotational speed of the cooling water pump in the second preset mapping relationship of this invention embodiment; Figure 5 This is a flowchart illustrating the cooling water pump control process in an embodiment of the present invention. Figure 6 This is a flowchart of the ECU control process in an embodiment of the present invention.

[0018] Among them, 1-cooling water pump controller; 2-cooling water pump 2. Detailed Implementation

[0019] 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, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the 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, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] The following description, with reference to the accompanying drawings, describes a cooling water pump control method, system, and vehicle according to embodiments of the present invention. In the prior art, a commonly used intelligent cooling water pump 2 is controlled by a duty cycle generated through pulse width modulation. The cooling water pump controller 1 receives different duty cycles from the engine control unit and controls the pump to rotate at different target speeds, thereby achieving the purpose of controlling the coolant flow rate at different speeds.

[0023] In existing PWM-type cooling water pump control systems, such as Figure 1As shown, the ECU outputs a PWM signal to the water pump controller 1 through a predetermined pin. The water pump controller 1 uses the duty cycle of this PWM signal as the sole control variable for the water pump 2, driving the water pump motor to operate at different target speeds to provide coolant flow rates suitable for different operating conditions. However, when a short circuit, open circuit, or poor contact occurs in the signal transmission line between the ECU and the water pump controller 1, the water pump controller 1 will receive an invalid duty cycle signal. The water pump controller 1 will then drive the water pump 2 to operate at maximum speed for an extended period. If the water pump operates at high speed for a prolonged period, it will cause the vehicle battery to deplete and also generate significant noise.

[0024] The existing PWM-type coolant pump control system mentioned in the background technology above only uses the PWM duty cycle output by the ECU as the single control quantity of the coolant pump 2. When a short circuit, open circuit, or poor contact occurs in the signal transmission line between the ECU and the coolant pump controller 1, the coolant pump controller 1 will receive an invalid duty cycle control signal and run at maximum speed for a long time. If the water pump is running at high speed for a long time, it will not only easily cause the vehicle battery to be depleted, but also generate a lot of noise. At the same time, the coolant pump 2 may continue to run at high speed even when the engine is off (key off), resulting in energy waste and unnecessary mechanical wear of components. The control reliability and energy saving of the system under fault conditions and ignition off conditions need to be improved.

[0025] To address the problem of prolonged high-speed operation of the water pump 2 when it receives an invalid duty cycle, leading to battery depletion and noise, this invention proposes a water pump control method, system, and vehicle. Building upon the traditional method of using a PWM signal as the first control signal for the water pump 2, an ignition IGN signal is introduced as the second control signal, allowing the water pump controller 1 to be jointly controlled by both the PWM and ignition IGN signals. When the ignition IGN signal is active, the relationship between the water pump 2's rotational speed and the received duty cycle is as follows: Figure 2 The ECU is controlled by the first preset mapping relationship shown. In this mapping relationship, the ECU can precisely adjust the duty cycle within the linear adjustment range of D3 ≤ duty cycle ≤ D4, thereby linearly adjusting the water pump speed to control the coolant flow and precisely manage the intake air temperature. When D4 ≤ duty cycle ≤ 100, the water pump is limited to operate at the calibrated maximum speed to provide maximum cooling capacity under extreme conditions such as high engine load and excessively high coolant temperature, preventing engine overheating. When D1 ≤ duty cycle ≤ D2, the duty cycle is the invalid duty cycle output when the PWM control signal is abnormal. The water pump will not stop rotating when it receives this duty cycle and will run at maximum speed. When the ignition IGN signal is OFF, the speed of the cooling water pump 2 is related to the received duty cycle. Figure 4As shown, the cooling water pump controller 1 divides the PWM duty cycle into intervals according to the second preset mapping relationship. Only within the effective interval of D3≤duty cycle≤D5, the corresponding target speed is output according to the duty cycle in a linear law, providing adjustable cooling capacity for the residual heat cooling after the engine is turned off. When the duty cycle ≤D3 or the duty cycle ≥D5, that is, when it is in the first invalid interval and the second invalid interval, the cooling water pump 2 is directly controlled to stop running, so that the invalid duty cycle no longer corresponds to the highest speed. By introducing a first invalid interval, an effective interval, and a second invalid interval in the second preset mapping relationship, and stipulating that the cooling water pump 2 stops operating when the PWM duty cycle falls into the invalid interval, this embodiment of the invention can effectively prevent the cooling water pump 2 from running at high speed for a long time under Key Off conditions and when the PWM duty cycle is abnormal due to signal line faults. This significantly reduces the risk of battery drain and reduces unnecessary noise and mechanical wear of the water pump. At the same time, by setting a linear adjustment interval and a maximum speed threshold in the first preset mapping relationship, and setting an effective interval and an invalid interval in the second preset mapping relationship, the cooling water pump 2 speed is controlled under different operating conditions using simple threshold comparison and piecewise functions. This makes the control logic clear, the implementation cost low, and easy to deploy on the existing cooling water pump controller 1. It can achieve smooth and predictable adjustment of coolant flow under normal engine operating conditions, and ensure sufficient cooling capacity under extreme conditions such as high engine load or high temperature. In ignition off and fault conditions, the pump stop strategy reduces energy consumption. Overall, it achieves more intelligent, energy-saving, and reliable control of the cooling water pump 2, which is beneficial to ensuring engine power output, improving fuel economy, and extending the life of related components.

[0026] Specifically, such as Figure 3 As shown, the input terminal of the cooling water pump controller 1 is connected to the PWM signal line and the IGN signal line output by the engine control unit ECU, respectively, forming a dual-signal control structure. Figure 5 This is a schematic flowchart of the cooling water pump 2 control method according to an embodiment of the present invention.

[0027] Specifically, in embodiments of the present invention, such as Figures 3-5 As shown, the control method for cooling water pump 2 includes the following steps: Step S101: Obtain the first control signal.

[0028] Specifically, in this embodiment, the first control signal is a pulse width modulation (PWM) signal, which is output by the engine control unit (ECU) through pin 1. The ECU calculates the target water pump speed according to a preset control strategy based on parameters such as engine coolant temperature, intake air temperature, engine speed, ambient temperature, and air conditioning operating conditions. It then converts the target speed into a PWM signal with a corresponding duty cycle and outputs it to the water pump control unit 1 through pin 1. Pin 2 carries the feedback signal output from the water pump control unit 1 to the ECU, allowing the ECU to obtain the operating status information of the water pump control unit 1. The duty cycle of the PWM signal is used to characterize the target speed of the water pump 2.

[0029] Step S102: Obtain the second control signal.

[0030] Specifically, in this embodiment, the second control signal is the ignition IGN signal. The ignition IGN signal is generated by the vehicle ignition switch or the body control module and transmitted to the coolant pump control unit 1 to characterize the vehicle's ignition status. Typically, when the ignition switch is in the key-on state, the ignition IGN signal is in the on state; when the ignition switch is in the key-off state, the ignition IGN signal is in the off state.

[0031] Step S103: Select different control strategies to control the speed of cooling water pump 2 according to the state of the second control signal.

[0032] Specifically, in this embodiment, after receiving the ignition IGN signal, the cooling water pump control unit 1 first determines whether the ignition IGN signal is in an on or off state, and selects to call either the first preset mapping relationship or the second preset mapping relationship accordingly, thereby realizing condition-based control: when the second control signal ignition IGN signal is in an on state, the engine control unit ECU calls the first preset mapping relationship; when the second control signal ignition IGN signal is in an off state, the engine control unit ECU calls the second preset mapping relationship.

[0033] Step S104: When the second control signal is in the on state, the speed of the cooling water pump 2 is determined by the duty cycle of the first control signal according to the first preset mapping relationship.

[0034] Specifically, in this embodiment, when the second control signal (ignition IGN signal) is in the on state, the vehicle is in normal driving or engine running condition, at which time the cooling demand is high. The cooling water pump control unit 1 determines the speed of the cooling water pump 2 based on the duty cycle of the first control signal according to the first preset mapping relationship.

[0035] The first preset mapping relationship can be any monotonic or piecewise function relationship, used to describe the change in water pump speed with PWM duty cycle during engine operation. For example, corresponding target speed values ​​can be set for different duty cycle ranges, or a function can be used to convert duty cycle to speed.

[0036] The engine control unit (ECU) generates a target water pump speed based on the corresponding value in the first preset mapping relationship of the current duty cycle, and converts the target speed into a drive command for the water pump motor.

[0037] Step S105: When the second control signal is in the off state, the speed of the cooling water pump 2 is determined by the duty cycle of the first control signal according to the second preset mapping relationship.

[0038] Specifically, in this embodiment, when the second control signal ignition IGN signal is off, the vehicle is in a standby or off-state condition. To prevent the water pump from running for a long time and causing the battery to run out of power, the engine control unit (ECU) differentiates the PWM duty cycle in different intervals according to the second preset mapping relationship, and determines the speed of the cooling water pump 2 according to the duty cycle of the first control signal.

[0039] Step S106: In the second mapping relationship, when the duty cycle of the first control signal is in the invalid range, the cooling water pump 2 is controlled to stop operating.

[0040] Specifically, in this embodiment, a duty cycle interval is pre-set as an invalid interval in the second preset mapping relationship. The duty cycle within this interval is uniformly regarded as an invalid control quantity. When the cooling water pump control unit 1 detects that the PWM duty cycle is in the invalid interval, it no longer calculates the corresponding water pump speed, but directly outputs a pump stop command to stop the cooling water pump 2.

[0041] The invalid range can be set as a range of duty cycles to cover specific duty cycle values ​​that may occur due to abnormal control signals or wiring harness faults, preventing these duty cycles from causing the water pump to run at high speed when the ignition is off. When the ignition IGN signal is off and the PWM duty cycle received by the water pump control unit is in the invalid range, the control unit outputs a pump stop command, causing the coolant pump 2 motor to stop running. This setting ensures that even if a short circuit or open circuit occurs in the signal line between the ECU and the water pump controller, causing the PWM duty cycle to abnormally remain fixed within the invalid range, the water pump will not be driven to run at maximum speed when the ignition IGN signal is off, i.e., when the vehicle is off or in standby mode, thus avoiding battery drain and noise problems.

[0042] Specifically, in the above embodiments of the present invention, by introducing a second control signal ignition IGN signal and employing different mapping relationships in the two states of ignition on and ignition off, the operating state of the cooling water pump 2 is matched with the vehicle's ignition state. When the ignition IGN signal is off, the pump is stopped in the invalid range. In the second preset mapping relationship, when the PWM duty cycle is in the invalid range, the pump is directly stopped, avoiding erroneous operation and prolonged high-speed operation of the cooling water pump 2 due to invalid duty cycles in the ignition off state. By identifying invalid duty cycles and stopping the pump in the ignition off state, unnecessary consumption of battery power is reduced, and unnecessary mechanical wear of the water pump is avoided.

[0043] Furthermore, in some embodiments of the present invention, such as Figure 2 As shown, in the first preset mapping relationship, when the duty cycle of the first control signal is in the linear adjustment range, the speed of the cooling water pump 2 is linearly related to the duty cycle; when the duty cycle is greater than or equal to the maximum speed threshold, the cooling water pump 2 is controlled to run at the maximum speed.

[0044] Specifically, in this embodiment, a continuous interval within the PWM duty cycle range is selected as the linear adjustment interval. Within this interval, the water pump speed changes linearly with the duty cycle. For example, the duty cycle range is divided into several intervals, one of which is defined as the linear adjustment interval. Here, RPM is the target water pump speed, Duty is the PWM duty cycle, b1 is the minimum speed, c1 is the maximum speed, and D4 is the maximum threshold. When the duty cycle is D3, it corresponds to the minimum speed b1 in the linear relationship. When the duty cycle is D4, i.e., when the duty cycle equals the maximum threshold D4, it corresponds to the maximum speed c1 in the linear relationship. Furthermore, this invention does not specifically limit the linear function. Through this linear mapping, during engine operation, the ECU only needs to change the duty cycle within this interval to achieve continuous adjustment of the water pump speed, which is beneficial for finely controlling the coolant flow rate within a certain range.

[0045] A maximum speed threshold is set within the PWM duty cycle range. This threshold is located at the high end of the linear adjustment range or outside it, and is used to distinguish between the linear speed regulation range and the maximum speed operating range. When the duty cycle is less than the maximum speed threshold and is within the linear adjustment range, the pump speed is calculated by the above linear relationship. When the duty cycle is greater than or equal to the maximum speed threshold, the control unit limits the target speed of the pump to the preset maximum speed value, and it no longer changes with further increases in the duty cycle.

[0046] The maximum speed threshold can be calibrated based on factors such as the maximum efficiency point of the water pump and the extreme cooling requirements of the engine. This allows the water pump to quickly enter the highest speed operating state when the engine heat load is high, by increasing the duty cycle to the threshold or above.

[0047] In one embodiment of the present invention, the rotational speed of the water pump and the duty cycle of the receiver are, for example... Figure 2 As shown, when D3≤Duty≤D4, that is, when the duty cycle of the first control signal is between D3 and the maximum speed threshold D4, it is in the linear speed adjustment zone, and the speed of the water pump 2 increases linearly with the increase of the duty cycle. Within this range, the ECU can precisely adjust the duty cycle to control the coolant flow and precisely manage the intake air temperature. Setting a linear adjustment zone improves control accuracy. Within this range, the pump speed and duty cycle are linearly related, allowing vehicle calibration personnel to adjust the cooling characteristics through linear parameters, achieving smooth and predictable adjustment of the coolant flow under normal engine conditions. When D4≤Duty≤100, that is, when the duty cycle of the first control signal is greater than or equal to the maximum speed threshold D4 and less than or equal to 100, the water pump controller 1 limits the speed of the water pump 2 to the calibrated maximum speed. The pump operates at maximum speed, which can control the coolant to run at maximum flow when the temperature is too high, thereby accelerating system cooling to cope with high engine load and excessively high coolant temperature conditions. The specific value of the maximum speed threshold can be determined through calibration based on the performance parameters of the water pump 2 and the overall vehicle cooling requirements, and is not limited to the specific value in the illustrated embodiment. Setting the maximum speed threshold ensures cooling capacity under extreme operating conditions. When the duty cycle reaches or exceeds the maximum speed threshold, the water pump is controlled to operate at its maximum speed, ensuring sufficient cooling capacity for the engine under extreme conditions such as high load or high temperature, preventing overheating. When D1≤Duty≤D2, i.e., the duty cycle of the first control signal is between D1 and D2, this duty cycle is the invalid duty cycle output when the PWM control signal is abnormal. Upon receiving this duty cycle, the water pump will not stop rotating but will operate at its maximum speed. Thus, even if the PWM control signal is abnormal, such as a short circuit, open circuit, or loss of control signal, the water pump controller 1 will not completely stop working but will maintain maximum speed operation. In the event of an abnormal control signal, the water pump is prevented from completely stopping, preventing the engine from overheating due to lack of cooling, especially under high load and high temperature conditions, ensuring that the cooling system can still provide maximum flow cooling capacity. It can maintain cooling even when the system malfunctions, preventing engine overheating and potential system damage.

[0048] Overall, this invention achieves a balance between control precision and safety margin by setting a linear range and a maximum speed threshold. This is achieved through linear speed regulation to improve control accuracy under most daily operating conditions, and maximum speed operation to improve reliability under extreme conditions. The entire cooling water pump 2 control method divides the duty cycle into multiple ranges using a segmented control strategy, and sets clear speed change rules for each range. This ensures that the cooling water pump 2 can balance precise adjustment, maximum cooling, and fault protection under different operating conditions, avoiding pump stoppage or over-operation due to abnormal control signals. Through this reasonable segmentation, the control system can maintain high reliability and safety under complex and variable operating conditions, reducing the impact of system failures. Under normal operating conditions, the system maintains a stable cooling effect through a precise linear adjustment range (D3≤Duty≤D4); under extreme conditions, the maximum speed threshold above D4 rapidly increases cooling capacity; and in the event of abnormal control signals, maximum speed operation ensures that the cooling water pump 2 always provides sufficient cooling flow. The multiple control methods of the overall system effectively improve cooling capacity and system stability, especially in emergency situations such as excessive load or abnormal rise in coolant temperature.

[0049] Furthermore, in some embodiments of the present invention, such as Figure 4 As shown, in the second preset mapping relationship, when the duty cycle of the first control signal is in the effective range, the cooling water pump 2 is controlled to run at the corresponding speed according to the duty cycle; when the duty cycle of the PWM signal is in the first invalid range and the second invalid range, the cooling water pump 2 is controlled to stop running.

[0050] Specifically, in this embodiment, the present invention selects a continuous interval within the PWM duty cycle range as the effective interval under the second preset mapping relationship. When the duty cycle is within the effective interval, it is considered that the duty cycle can reflect the cooling demand. Within this interval, the cooling water pump control unit 1 calculates the corresponding water pump speed based on the duty cycle, for example, by using a linear or nonlinear function relationship to map the duty cycle to the target water pump speed. By setting an effective interval in the second preset mapping relationship, even in the ignition-off state, a limited speed control capability can be provided to the water pump within a certain range based on the duty cycle to meet the residual cooling demand for a short period of time.

[0051] Specifically, in this embodiment, the present invention reserves a section on both sides of the PWM duty cycle range as a second invalid interval. When the PWM duty cycle falls into the first invalid interval and the second invalid interval, the cooling water pump controller 1 treats it as another type of invalid control signal; when the cooling water pump controller 1 detects that the duty cycle is in the first invalid interval and the second invalid interval, it directly outputs a pump stop command, causing the cooling water pump 2 to stop operating. In this way, in the ignition off state, the water pump will not be driven to run regardless of whether the duty cycle falls into the first invalid interval or the second invalid interval.

[0052] Specifically, in the above embodiments of the present invention, by adding a distinction between an effective range and a first and second ineffective range in the second preset mapping relationship, necessary residual cooling capacity can be retained. Within the effective range, the water pump speed is controlled according to the duty cycle, providing adequate cooling even when the engine has just been turned off and the temperature is still high, reducing the risk of localized heat buildup. By setting a first and second ineffective range in the second preset mapping relationship and stopping the pump within these ranges, pump stop protection can be implemented for two different types of abnormal duty cycles, such as extremely low and extremely high values, significantly improving the system's fault tolerance to abnormal signals. In the ignition-off state, only the duty cycle within the effective range is allowed to drive the water pump, preventing the water pump from mistakenly operating at high speed under abnormally high duty cycles, thus helping to reduce battery power consumption.

[0053] Furthermore, in some embodiments of the present invention, the first invalid interval is a duty cycle less than or equal to a first threshold, the second invalid interval is a duty cycle greater than or equal to a second threshold, and the valid interval is between the first threshold and the second threshold.

[0054] Specifically, in this embodiment, two duty cycle boundary values ​​are set: a first threshold and a second threshold. The entire duty cycle range is divided into three intervals: a first invalid interval, a second invalid interval, and an effective interval. A first threshold is set within the PWM duty cycle interval. The portion of the duty cycle less than or equal to this threshold is defined as the first invalid interval; that is, the interval where Duty ≤ the first threshold is the first invalid interval. When the duty cycle of the PWM control signal is less than or equal to this low duty cycle range (the first threshold), the duty cycle of the PWM control signal is within the first invalid interval. The duty cycle of the PWM control signal is considered invalid, and the cooling water pump controller 1 controls the cooling water pump 2 to stop operating. By introducing the first threshold, low duty cycle regions can be uniformly classified as the first invalid interval, simplifying software implementation and facilitating interval judgment using simple comparison operations in the program. A second threshold is set on the high side of the duty cycle interval. The portion of the duty cycle greater than or equal to this threshold is defined as the second invalid interval; that is, the interval where Duty ≥ the second threshold is the second invalid interval. The second threshold can be set to a value close to the upper limit of the duty cycle to identify abnormally high duty cycles or reserved high-invalid duty cycle regions. When the duty cycle of the PWM control signal reaches or exceeds the second threshold, this high duty cycle range, the duty cycle is considered invalid, and the cooling water pump controller 1 controls the cooling water pump 2 to stop operating. This high duty cycle invalid range usually corresponds to abnormally high duty cycles that occur under fault conditions such as signal line short circuits to power supply. By uniformly defining this range as invalid, it is possible to avoid the water pump being mistakenly triggered to run at high speed due to abnormally high duty cycles when the ignition is off. The duty cycle range between the first threshold and the second threshold is defined as the effective range, that is, the range where the first threshold ≤ Duty ≤ the second threshold is the effective range. When the duty cycle of the PWM control signal is within this effective range, the cooling water pump controller 1 considers the duty cycle as an effective control quantity and converts the duty cycle into the corresponding target speed of the water pump according to the second preset mapping relationship, so that the cooling water pump 2 runs at a speed adapted to the duty cycle. In a preferred embodiment: (1) The first invalid interval is the interval with a duty cycle less than or equal to the first threshold.

[0055] The first invalid interval, defined as a duty cycle less than or equal to a first threshold, can be understood as follows: when the duty cycle of the PWM control signal falls within the low duty cycle range of 0 to the first threshold, the current PWM duty cycle is considered invalid, possibly due to faults such as wiring harness grounding or short circuits. The cooling water pump controller 1 no longer drives the water pump based on this duty cycle, but directly controls the water pump to stop operating. The first threshold can be calibrated based on specific water pump characteristics, ECU output capability, and wiring harness noise levels; for example, the first threshold can be 5% to 15%. In one embodiment of the present invention, such as... Figure 4As shown, in one embodiment, the first threshold can be set to D3, and the first invalid interval is the interval where the duty cycle is less than or equal to D3. The duty cycle of the PWM control signal within the range of 0 to D3 is regarded as an invalid duty cycle.

[0056] (2) The second invalid interval is the interval with a duty cycle greater than or equal to the second threshold.

[0057] The second threshold can be set in the medium-high duty cycle region, such as 50% to 80%, representing a high duty cycle operating condition. When Duty ≥ the second threshold, with IGN OFF, such a high flow rate is usually not required from the pump, and this range is classified as an invalid duty cycle range. In one embodiment of the present invention, as... Figure 2 As shown, the second threshold can be set to D5, and the second invalid interval is the interval with a duty cycle greater than or equal to D5.

[0058] (3) The effective range is between the first threshold and the second threshold.

[0059] When the first threshold ≤ Duty ≤ the second threshold, the current duty cycle is considered valid, and the corresponding water pump speed is adjusted linearly or monotonicly by the second preset mapping relationship. This range can be used to provide limited but controllable cooling flow in certain specific operating conditions, such as when the engine has just been turned off and the coolant temperature is still high. In one embodiment of the invention, as... Figure 2 As shown, the first threshold can be set to D3, and the second threshold can be set to D5. The effective range is the range of D3≤Duty≤D5.

[0060] Specifically, in the above embodiments of the present invention, by introducing a first threshold and a second threshold, the first invalid interval, the valid interval, and the second invalid interval are uniformly represented by simple numerical boundaries. The boundaries of each interval are clearly defined by the two thresholds, and the software only needs to use simple comparison operations to complete the interval judgment, reducing the complexity of the control logic. By adjusting the values ​​of the first threshold and the second threshold, engineers can easily adjust the length and position of each interval to adapt the system to the characteristics of different vehicles or different models of water pumps. By limiting the numerical thresholds, it is possible to precisely control which duty cycles are considered invalid, further improving the accuracy of abnormal signal identification and achieving highly stable pump shutdown protection.

[0061] Furthermore, in some embodiments of the present invention, in the second preset mapping relationship, when the duty cycle of the first control signal is in the effective range between the first threshold and the second threshold, the rotational speed of the cooling water pump 2 is linearly related to the duty cycle; when the duty cycle is less than or equal to the first threshold, or greater than or equal to the second threshold, the cooling water pump 2 is controlled to stop operating.

[0062] Specifically, in the second preset mapping relationship, when the duty cycle of the first control signal pulse width modulation (PWM) signal is within the effective range between the first threshold and the second threshold, the speed of the cooling water pump 2 is linearly related to the duty cycle. In practical applications, embodiments of the present invention define the range between the first and second thresholds as the operating range where the water pump is allowed to operate when the second control signal ignition IGN signal is off. Within the linear operating range, the target speed of the water pump changes with the duty cycle at a fixed ratio, which can be described by a linear function relationship. That is, for every fixed increase in the duty cycle, the water pump speed increases by a fixed amount, and the speed-duty cycle curve is a continuous monotonic straight line. Thus, when the control unit adopts the second preset mapping relationship, it only needs to apply a linear function or linear interpolation relationship based on the position of the current duty cycle within the effective range to obtain the target speed, which is beneficial for achieving predictable and adjustable control of the water pump speed under the ignition-off state.

[0063] In the second preset mapping relationship, when the duty cycle of the first control signal pulse width modulation (PWM) signal is less than or equal to the first threshold, that is, when the duty cycle of the first control signal pulse width modulation (PWM) signal falls into the first invalid interval, the cooling water pump 2 is controlled to stop operating; or when the duty cycle of the first control signal pulse width modulation (PWM) signal is greater than or equal to the second threshold, that is, when the duty cycle of the first control signal pulse width modulation (PWM) signal falls into the second invalid interval, the cooling water pump 2 is controlled to stop operating.

[0064] In practical applications, in the embodiments of the present invention, when the second control signal ignition IGN signal is off, low duty cycles below the first threshold are all considered invalid duty cycles, and the water pump does not run; high duty cycles above the second threshold are also considered invalid duty cycles, and the water pump does not run; the water pump is only allowed to run linearly within the effective range between the first threshold and the second threshold.

[0065] With this design, the second preset mapping relationship is essentially a piecewise function. The invalid intervals at both ends correspond to a rotational speed of 0, while the valid interval in the middle corresponds to a linearly rising or linearly changing curve. This allows the cooling water pump 2 to operate linearly and adjustablely only within a carefully selected valid interval when the second control signal (ignition IGN) is off, thus meeting the residual heat cooling needs for a short period after engine shutdown. A large range of duty cycles on both sides of the valid interval are classified as invalid intervals, and a unified pump shutdown strategy is adopted to prevent the water pump from malfunctioning or running for extended periods when the ignition is off due to abnormal duty cycles. The linear relationship simplifies calibration and ensures the continuity and predictability of cooling capacity changes with the duty cycle.

[0066] Combination Figures 2 to 4As shown, the working principle of the cooling water pump control method of the present invention will be explained in detail with reference to an embodiment.

[0067] This invention provides a cooling water pump control method. Based on existing PWM cooling water pump control, an ignition IGN signal is introduced as a second control signal. When the ignition IGN signal is ON, the relationship between the pump speed and duty cycle follows a first preset mapping relationship, i.e. Figure 2 The curve in the diagram is used for control; when the ignition IGN signal is OFF, the relationship between the water pump speed and the duty cycle follows the second preset mapping relationship, i.e. Figure 4 The curves in the curves are controlled.

[0068] exist Figure 4 The ignition IGN is shown as being OFF: Specifically, in this embodiment, such as Figure 4 As shown, in the second preset mapping relationship, within the effective interval between the first threshold and the second threshold, the rotational speed of the cooling water pump 2 is linearly related to the duty cycle. Here, RPM is the target rotational speed of the water pump, Duty is the PWM duty cycle, b2 is the minimum rotational speed, c2 is the maximum rotational speed, D3 is the first threshold, D4 is an intermediate operating point, and D5 is the second threshold. The linear slope is determined through vehicle calibration; this invention does not require specific limitations on the linear function. When the duty cycle is D3, it corresponds to the minimum rotational speed b2 in the linear relationship; when the duty cycle is D4, it corresponds to the maximum rotational speed c2 in the linear relationship.

[0069] When D3 ≤ the duty cycle of the first control signal pulse width modulation (PWM) signal ≤ D4, a monotonically increasing linear curve is plotted: as the duty cycle gradually increases from D3 to D4, the target speed of the cooling water pump 2 increases linearly with the duty cycle; that is, within the effective range of D3 to D4, the target speed of the cooling water pump 2 increases linearly with the duty cycle. When D4 ≤ the duty cycle of the first control signal pulse width modulation (PWM) signal ≤ D5, the cooling water pump 2 operates at its highest speed as the duty cycle increases. In other words, when the duty cycle of the first control signal pulse width modulation (PWM) signal is between D3 and D5, the duty cycle received by the cooling water pump controller 1 is the effective duty cycle, and the cooling water pump 2 is controlled by the PWM control signal issued by the ECU. For example, if the engine temperature remains high for a period of time after ignition is turned off, the ECU outputs a duty cycle between D3 and D5. At this time, the duty cycle received by the water pump controller is the effective duty cycle. The water pump is controlled by the PWM control signal issued by the ECU. Based on the current vehicle operating parameters, the current duty cycle value is calculated, thereby adjusting the water pump speed to cool the engine or related components. As the duty cycle gradually decreases, the water pump speed decreases linearly at the same slope. Finally, when the duty cycle decreases to D3 or below, the water pump stops operating, achieving a smooth transition from cooling to pump shutdown.

[0070] When the duty cycle of the first control signal pulse width modulation (PWM) signal is less than D3, or the duty cycle of the first control signal pulse width modulation (PWM) signal is greater than D5, the water pump controller determines that the current duty cycle is invalid. In these two intervals, the target speed of the water pump is 0, that is, the water pump does not run and does not work, and the speed is zero. With this setting, when the ignition switch is in the off state, if a circuit fault causes the PWM signal to be abnormally low or high in duty cycle, the corresponding duty cycle will naturally fall into the first invalid interval or the second invalid interval, and the water pump will stop running immediately. This avoids the problem of the water pump running at high speed for a long time when receiving an invalid duty cycle, which leads to the depletion of the vehicle battery, as is the case in the traditional solution.

[0071] Within the effective range described above, the pump speed increases proportionally with the increase of the duty cycle to balance cooling demand and energy consumption. Through this linear relationship, when the duty cycle changes within the effective range, the pump speed changes proportionally with the duty cycle, thus providing different levels of cooling capacity as needed even when the ignition is off.

[0072] Figure 5 This is a flowchart illustrating the control method for the cooling water pump 2 according to an embodiment of the present invention. The cooling water pump 2 control method of this embodiment is applied in a PWM-type intelligent cooling water pump 2 control system after adding a second control signal, the ignition IGN signal. In this system, the cooling water pump controller 1 simultaneously receives the first control signal PWM and the second control signal ignition IGN signal from the engine control unit ECU, and selects different duty cycle-speed mapping relationships according to the state of the ignition IGN signal, thereby performing condition-based control of the speed of the cooling water pump 2.

[0073] Specifically, such as Figure 3 and Figure 5 As shown, the cooling water pump controller 1 can execute the following process during operation: First, the cooling water pump controller 1 receives the target PWM duty cycle calculated by the ECU based on the current vehicle operating parameters, which is the duty cycle of the first control signal, and uses this duty cycle as the target control quantity of the water pump at the current moment.

[0074] Subsequently, the coolant pump controller 1 samples the second control signal, the ignition IGN signal, and determines whether the ignition IGN signal is ON. If the determination result is that the ignition IGN signal is ON, it indicates that the vehicle is in Key On, engine ignition, or running state, and the cooling demand is high; if the determination result is that the ignition IGN signal is OFF, it indicates that the vehicle is in Key Off or standby state. In this case, the coolant pump 2 should be prevented from operating for a long time under invalid duty cycle conditions.

[0075] When the ignition IGN signal is determined to be ON, the cooling water pump controller 1 calls the first preset mapping relationship to map the current PWM duty cycle to the corresponding target water pump speed, and then... Figure 2 The linear relationship shown drives the operation of the cooling water pump 2. That is, within the linear adjustment range, the speed of the cooling water pump 2 is continuously adjusted by the duty cycle. When the duty cycle reaches or exceeds the maximum speed threshold, it runs at the highest speed to meet the cooling requirements of the engine under high load or high temperature conditions.

[0076] When the ignition IGN signal is determined to be OFF, the cooling water pump controller 1 switches to the second mapping relationship, second preset mapping relationship control mode, according to... Figure 4 The duty cycle-speed curve shown compares the current PWM duty cycle with a preset duty cycle range: when the duty cycle is between D3 and D5, this range is considered valid. The water pump controller 1 operates the water pump 2 at a linear speed adapted to the duty cycle based on the linear relationship between D3 and D5, providing necessary residual heat cooling when the engine has just been turned off and the temperature is still high; when the duty cycle is less than or equal to D3, or greater than or equal to D5, the duty cycle is determined to be invalid, corresponding to the first invalid range and the second invalid range. The water pump controller 1 directly outputs a pump stop command, causing the water pump 2 to stop running and its speed to be 0.

[0077] After the above two operating conditions are completed, the cooling water pump 2 will run or stop running according to the determined target speed, and the corresponding process will end.

[0078] pass Figure 5 The control flow shown in this invention introduces the ignition IGN signal as a second control signal, based on the traditional PWM duty cycle control. This allows the coolant pump controller 1 to automatically switch between different duty cycle-speed mapping relationships when the ignition is on and off: when the ignition IGN signal is ON, the first mapping relationship and the first preset mapping relationship are used to ensure normal engine cooling performance; when the ignition IGN signal is OFF, the second mapping relationship and the second preset mapping relationship are used, and the pump is stopped in the invalid duty cycle range. This avoids the invalid duty cycle being interpreted as the maximum speed due to faults such as short circuits or open circuits, thereby preventing the coolant pump 2 from running at high speed for a long time after the vehicle is turned off, reducing the risk of battery depletion, reducing unnecessary noise, and improving the intelligence and reliability of the coolant pump 2 control system.

[0079] Figure 6 This is a schematic diagram of the engine control unit (ECU) control flow according to an embodiment of the present invention, used to illustrate how the ECU calculates the target PWM duty cycle of the water pump based on the current operating conditions of the vehicle, and correlates it with... Figure 5 The control process of the cooling water pump 2 shown is coordinated to achieve the coordinated control of the vehicle cooling system.

[0080] Specifically, such as Figure 6 As shown, the control flow of the ECU may include the following steps: First, the ECU collects real-time vehicle operating parameters, such as engine operating status, coolant temperature, intake air temperature, environmental conditions, and vehicle thermal management requirements. Based on a preset calibration strategy, it calculates the target speed of the coolant pump 2 required at the current moment. The ECU then converts this target speed into the corresponding PWM duty cycle and generates a target PWM control signal, i.e., the first control signal, for use by the coolant pump controller 1.

[0081] Then, the ECU determines whether the current vehicle status is Key On or Key Off based on the ignition switch status or vehicle power management information. When it is determined to be Key On, it indicates that the engine is in ignition or running state. The target PWM duty cycle output by the ECU will work together with the first preset mapping relationship of the coolant pump controller 1 to make the coolant pump controller 1 operate according to... Figure 2 The duty cycle-speed curve shown converts the target duty cycle into the corresponding target speed of the water pump, enabling normal cooling and fine speed control under engine operating conditions.

[0082] When the system is identified as Key Off, it indicates that the vehicle is in a standby or off-state. The ECU can still output a target PWM duty cycle for a short period based on the engine's residual heat to provide limited residual heat cooling when necessary. In this state, the coolant pump controller 1 will automatically switch to... Figure 4 The second mapping relationship shown is a second preset mapping relationship. It performs range judgment on the duty cycle output by the ECU: if the duty cycle falls within the effective range between D3 and D5, the duty cycle received by the water pump controller is the effective duty cycle. The water pump is controlled by the PWM control signal issued by the ECU. Based on the current vehicle operating parameters, the duty cycle value at the current moment is calculated, thereby adjusting the water pump speed so that the water pump runs at a moderate and adjustable speed; if the duty cycle is below D3 or above D5, that is, it falls into the first invalid range or the second invalid range, the water pump is directly controlled to stop running.

[0083] Figure 6 The ECU control flow shown is similar to Figure 5The water pump control processes shown correspond to each other: On the one hand, the ECU calculates the target PWM duty cycle of the water pump based on the current operating parameters, ensuring that cooling demand is planned uniformly at the vehicle level; on the other hand, by distinguishing between Key On and Key Off states, and using them in conjunction with the first, first, and second preset mapping relationships within the water pump controller 1, the same PWM duty cycle corresponds to different speed control strategies under different ignition states. In cases of ignition IGN signal shutdown, circuit fault, or abnormal duty cycle, the water pump controller 1 identifies the first and second invalid intervals defined by the D3 and D5 thresholds, directly stopping the pump to avoid operating at maximum speed during invalid duty cycles, effectively preventing battery depletion and unnecessary noise, while also considering vehicle safety, energy efficiency, and component lifespan.

[0084] A second aspect of the present invention provides a cooling water pump 2 control system for implementing the cooling water pump 2 control method as described in any of the above embodiments, specifically including: a main controller for issuing a first control signal and a second control signal; a control unit for receiving the first control signal and the second control signal, selecting to invoke a first preset mapping relationship or a second preset mapping relationship according to the state of the second control signal; and generating a control command for controlling the speed of the cooling water pump 2 based on the selected mapping relationship and the duty cycle of the first control signal.

[0085] Figure 3 This is a schematic diagram of the control principle of the cooling water pump 2 after adding a second control signal in an embodiment of the present invention.

[0086] like Figure 3 As shown, the control system of the cooling water pump 2 includes a main controller and a control unit.

[0087] Specifically, the main controller is used to issue the first control signal and the second control signal.

[0088] The main controller is preferably an engine control unit (ECU). The ECU collects information such as engine coolant temperature, intake air temperature, engine speed, throttle opening, ambient temperature, and air conditioning status. It calculates the target speed of the coolant pump 2 according to a preset control strategy and outputs a PWM signal with a corresponding duty cycle as the first control signal. The ECU or body control module also outputs an ignition IGN signal as the second control signal to indicate the ignition status of the vehicle.

[0089] The control unit is used to receive a first control signal and a second control signal, select to invoke a first preset mapping relationship or a second preset mapping relationship according to the state of the second control signal, and generate a control command for controlling the speed of the cooling water pump 2 based on the selected mapping relationship and the duty cycle of the first control signal.

[0090] The control unit can be a separate cooling water pump controller 1 or integrated into the water pump assembly. Its input terminal is connected to the PWM signal line and ignition IGN signal line output by the ECU, and its output terminal is connected to the water pump motor drive circuit. Specifically, in one embodiment of the present invention, the control unit is a cooling water pump 2 control unit, which includes a pump, a PWM input module, and a low-end drive module. The input terminal of the PWM input module is used to receive the first control signal pulse width modulation (PWM) signal output by the engine control unit ECU through pin 1, sample and decode the PWM signal to obtain the duty cycle of the first control signal. The low-end drive module can be understood as the low-side switch drive unit of the motor power output stage, used to control the on / off and duty cycle modulation of the cooling water pump 2 motor according to the target speed and control strategy given by the control unit.

[0091] Furthermore, in some embodiments of the present invention, a first preset mapping relationship or a second preset mapping relationship is selected to be invoked according to the state of the second control signal; based on the selected mapping relationship and the duty cycle of the first control signal, a control command for controlling the speed of the cooling water pump 2 is generated, including: when the second control signal is in the on state, determining the speed of the cooling water pump 2 according to the duty cycle of the first control signal based on the first preset mapping relationship; when the second control signal is in the off state, determining the speed of the cooling water pump 2 according to the duty cycle of the first control signal based on the second preset mapping relationship; wherein, in the second preset mapping relationship, when the duty cycle of the first control signal is in the invalid range, the cooling water pump 2 is controlled to stop operating.

[0092] When the cooling water pump controller 1 is running, it performs the following steps: (1) Receive and sample the first control signal PWM and the second control signal IGN.

[0093] (2) Determine the state of the second control signal: If the ignition IGN signal is in the on state, call the first preset mapping relationship; if the ignition IGN signal is in the off state, call the second preset mapping relationship.

[0094] (3) When the second control signal is in the open state, the speed of the cooling water pump 2 is determined by the duty cycle of the first control signal according to the first preset mapping relationship.

[0095] (4) When the second control signal is in the off state, the speed of the cooling water pump 2 is determined by the duty cycle of the first control signal according to the second preset mapping relationship.

[0096] (5) In the second preset mapping relationship, when the duty cycle of the first control signal is in the invalid range, the cooling water pump 2 is controlled to stop running. The control unit compares the PWM duty cycle with the first threshold and the second threshold. Once it is determined that Duty≤D3 or Duty≥D5, it outputs a pump stop command to stop the water pump motor.

[0097] Based on the above logic, the cooling water pump 2 control system adopts different mapping strategies when the second control signal ignition IGN signal is in the Key On and Key Off states, thereby improving the adaptability and safety of the control.

[0098] Furthermore, in some embodiments of the present invention, in the first preset mapping relationship, when the duty cycle of the first control signal is in the linear adjustment range, the rotational speed of the cooling water pump 2 is linearly related to the duty cycle; when the duty cycle is greater than or equal to the maximum speed threshold, the cooling water pump 2 is controlled to run at the maximum speed.

[0099] In one embodiment of the present invention, when the second control signal ignition IGN signal is in the on state: (1) When the duty cycle of the first control signal is in the linear adjustment range, the control unit calculates the target water pump speed according to the linear function or the table lookup result, so that the water pump speed is linearly related to the duty cycle, and achieves fine speed regulation to meet the cooling requirements under different engine loads.

[0100] (2) When the duty cycle is greater than or equal to the maximum speed threshold, the control unit sets the target water pump speed to the maximum value and outputs the corresponding drive control command so that the cooling water pump 2 runs at the maximum speed to accelerate the coolant circulation speed.

[0101] This implementation corresponds to the control logic of the cooling water pump 2 when the ignition is on. It can ensure that the water pump speed changes monotonically and is linearly adjustable with the PWM duty cycle under normal operating conditions, and can quickly enter the highest speed operating mode under extreme high temperature or heavy load conditions, thereby improving the safety of engine cooling.

[0102] Furthermore, in some embodiments of the present invention, in the second preset mapping relationship, when the duty cycle of the first control signal is in the effective range, the cooling water pump 2 is controlled to run at the corresponding speed according to the duty cycle; when the duty cycle of the PWM signal is in the first invalid range and the second invalid range, the cooling water pump 2 is controlled to stop running.

[0103] In one embodiment of the present invention, when the second control signal ignition IGN signal is in the off state, the control unit invokes the second preset mapping relationship and executes the following logic: (1) When the duty cycle is in the effective range: When the duty cycle of the first control signal is in the effective range, that is, when the duty is between the first threshold and the second threshold, the cooling water pump 2 is controlled to run at the corresponding speed according to the duty cycle. At this time, the duty cycle received by the water pump controller is the effective duty cycle. The water pump is controlled by the PWM control signal issued by the ECU. Based on the current vehicle operating parameters, the duty cycle value at the current moment is calculated, thereby adjusting the water pump speed to achieve appropriate cooling flow control.

[0104] (2) When the duty cycle is in the first invalid interval and the second invalid interval: When the duty cycle of the PWM signal is in the second invalid range, that is, when Duty≤First threshold or Duty≥Second threshold, the control unit regards the state as invalid. The duty cycle may be caused by wiring harness failure or abnormal software output. At this time, the control unit stops the cooling water pump 2 to avoid the water pump running at high speed in the Key Off state.

[0105] By pre-setting a second mapping relationship in the system scheme, the control unit can provide necessary short-term cooling function according to the duty cycle corresponding to the effective range when the ignition is off. On the other hand, it can quickly stop the pump when the duty cycle falls into the second invalid range to avoid abnormally high speed operation.

[0106] A third aspect of the present invention provides a vehicle including a cooling water pump 2 control system as described in any of the above embodiments.

[0107] By applying the cooling water pump 2 control system of this invention to a vehicle, the vehicle can still achieve precise control of the cooling water pump 2 speed using PWM signals during normal operation. When the ignition is off and the signal is abnormal, the cooling water pump 2 is stopped by jointly judging the IGN signal and the invalid duty cycle interval, thereby effectively preventing battery depletion and noise problems caused by prolonged high-speed operation of the water pump, and further improving the energy utilization efficiency and operational reliability of the vehicle. It should be understood that in the vehicle embodiment of this invention, the cooling water pump 2 control system can work in conjunction with existing vehicle control units such as the engine control unit and body control module without requiring significant modifications to the overall vehicle hardware architecture, and has good engineering feasibility.

[0108] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0109] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A cooling water pump control method, characterized in that, include: Obtain the first control signal; Obtain the second control signal; Based on the state of the second control signal, different control strategies are selected to control the speed of the cooling water pump; When the second control signal is in the on state, the speed of the cooling water pump is determined by the duty cycle of the first control signal according to the first preset mapping relationship; When the second control signal is in the off state, the speed of the cooling water pump is determined by the duty cycle of the first control signal according to the second preset mapping relationship; In the second preset mapping relationship, when the duty cycle of the first control signal is in the invalid range, the cooling water pump is controlled to stop operating.

2. The control method according to claim 1, characterized in that, In the first preset mapping relationship, when the duty cycle of the first control signal is in the linear adjustment range, the speed of the cooling water pump is linearly related to the duty cycle; when the duty cycle is greater than or equal to the maximum speed threshold, the cooling water pump is controlled to run at the maximum speed.

3. The control method according to claim 2, characterized in that, In the second preset mapping relationship, when the duty cycle of the first control signal is in the effective range, the cooling water pump is controlled to run at the corresponding speed according to the duty cycle; when the duty cycle of the first control signal is in the first invalid range and the second invalid range, the cooling water pump is controlled to stop running.

4. The control method according to claim 3, characterized in that, The first invalid interval is when the duty cycle is less than or equal to a first threshold, the second invalid interval is when the duty cycle is greater than or equal to a second threshold, and the valid interval is between the first threshold and the second threshold.

5. The control method according to claim 4, characterized in that, In the second preset mapping relationship, when the duty cycle of the first control signal is within the effective range between the first threshold and the second threshold, the rotational speed of the cooling water pump is linearly related to the duty cycle; when the duty cycle is less than or equal to the first threshold, or greater than or equal to the second threshold, the cooling water pump is controlled to stop operating.

6. A cooling water pump control system for implementing the method as described in any one of claims 1-5, characterized in that, include: The main controller is used to issue the first control signal and the second control signal. The control unit is used to receive a first control signal and a second control signal, and select to invoke a first preset mapping relationship or a second preset mapping relationship according to the state of the second control signal; Based on the selected mapping relationship and the duty cycle of the first control signal, a control command for controlling the speed of the cooling water pump is generated.

7. The control system according to claim 6, characterized in that, The step involves selecting to invoke either a first preset mapping relationship or a second preset mapping relationship based on the state of the second control signal; and generating a control command for controlling the cooling water pump speed based on the selected mapping relationship and the duty cycle of the first control signal, including... When the second control signal is in the on state, the speed of the cooling water pump is determined by the duty cycle of the first control signal according to the first preset mapping relationship; When the second control signal is in the off state, the speed of the cooling water pump is determined by the duty cycle of the first control signal according to the second preset mapping relationship; In the second preset mapping relationship, when the duty cycle of the first control signal is in the invalid range, the cooling water pump is controlled to stop operating.

8. The control system according to claim 7, characterized in that, In the first preset mapping relationship, when the duty cycle of the first control signal is in the linear adjustment range, the speed of the cooling water pump is linearly related to the duty cycle; when the duty cycle is greater than or equal to the maximum speed threshold, the cooling water pump is controlled to run at the maximum speed.

9. The control system according to claim 7, characterized in that, In the second preset mapping relationship, when the duty cycle of the first control signal is in the effective range, the cooling water pump is controlled to run at the corresponding speed according to the duty cycle; when the duty cycle of the first control signal is in the first invalid range and the second invalid range, the cooling water pump is controlled to stop running.

10. A vehicle, characterized in that, It includes a cooling water pump control system as described in any one of claims 6-9.

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