Predictive fan control method and system based on fuzzy hierarchical control

Abstract

The invention provides a predictive fan control method based on fuzzy hierarchical control. The predictive fan control method comprises the steps that vehicle basic information is provided for a VCU controller through a whole vehicle CAN bus; the VCU controller receives the front slope data sent by the map module and the current position information of the vehicle, performs road network reconstruction, and calculates the average slope of each preset length as the slope value of the current preset length; according to the slope value of the current preset length and the current vehicle speed, the engine power of the current preset length is calculated; the engine power and the environment temperature serve as input parameters of a fuzzy control algorithm, and target water temperature is calculated and output; according to the difference between the current water temperature and the target water temperature, the target fan rotating speed is calculated through a PID control algorithm. Based on the front terrain gradient, the whole vehicle driving power is estimated, the target water temperature is dynamically adjusted in combination with the current environment temperature, the control adaptability of different working conditions is improved, fan direct connection is reduced, power consumption is reduced, and the whole vehicle fuel economy is improved.

Description

Technical Field

[0001] The present invention provides a predictive fan control method and system based on fuzzy hierarchical control, and relates to the technical field of commercial vehicle intelligent control. Background Art

[0002] Commercial vehicles are used for long-distance logistics transportation, and fuel consumption is an important concern in this market segment. Traditional fuel-saving technologies, such as engine thermal efficiency, transmission efficiency, rolling resistance, etc., are limited in development due to cost or technical bottlenecks. Currently, all OEMs are striving to develop precise and optimal control of energy consumption systems to explore energy-saving space for the entire vehicle.

[0003] With the development of intelligent driving, accessory control based on map information has become a new energy-saving technology route. At present, the fan control of the whole vehicle is mostly controlled by the water temperature-fan speed curve. The calibration of this curve takes into account relatively single factors and the target water temperature control temperature is relatively fixed. In the actual driving process, it may cause unnecessary fan intervention, that is, there are problems such as poor adaptability to different working conditions and high fan power consumption during real-time control. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a predictive fan control method and system based on fuzzy hierarchical control to solve the technical problems existing in the prior art. The specific technical solution is as follows:

[0005] A predictive fan control method based on fuzzy hierarchical control comprises the following steps:

[0006] Send CAN signals to the VCU controller via the vehicle CAN bus to provide basic vehicle information;

[0007] Send the original data information of the vehicle's current position and the slope ahead to the VCU controller through the map module;

[0008] The VCU controller receives basic vehicle information, raw data information of the front slope and the current position information of the vehicle and reconstructs the road network, and calculates the average slope of each preset length as the slope value of the current preset length;

[0009] Calculate the engine power of the current preset length according to the slope value of the current preset length and the current vehicle speed;

[0010] The engine power and ambient temperature are used as input parameters of the fuzzy control algorithm to calculate the output target water temperature;

[0011] According to the difference between the current water temperature and the target water temperature, the PID control algorithm is applied to calculate the target fan speed.

[0012] Preferably, the basic vehicle information includes coolant temperature, vehicle speed and ambient temperature.

[0013] Preferably, the preset length is 300m.

[0014] Preferably, the calculation formula of the engine power is:

[0015]

[0016] Among them, m is the vehicle load, g is the gravity acceleration, f is the rolling damping coefficient, α is the road slope, C D is the air resistance coefficient, A is the windward area, u a is the driving speed.

[0017] Preferably, the target water temperature is calculated using a fuzzy control algorithm and a quadratic function is used for fitting control to adapt to the trend of water temperature changes.

[0018] Further, the target water temperature calculation cycle is set to T, the target water temperature control cycle is set to t, the target water temperature of the previous calculation cycle is set to tem1, and the template water temperature of the next calculation cycle is set to tem2;

[0019] When tem1>tem2, assuming tem1-tem2=s, then the target water temperature is sent at time t When tem1<tem2, assuming tem2-tem1=s, then the target water temperature is sent at time t

[0020] Preferably, the specific method of applying the PID control algorithm to calculate the target fan speed is: setting the integral separation coefficient to adjust the integral action strength, setting the integral saturation limit threshold to solve the integral saturation problem, adding a feedforward table with ambient temperature and predicted power as influencing factors, and using feedforward control to correct the PID control to improve the system response speed.

[0021] A predictive fan control system based on fuzzy hierarchical control, comprising:

[0022] CAN bus, used to send CAN signals to the VCU controller to provide basic vehicle information;

[0023] Map module, used to send the original data information of the vehicle's current position and the slope ahead to the VCU controller;

[0024] The VCU controller has a built-in predictive fan control package, which is used to receive the original data information of the basic information of the vehicle, the current position and the slope ahead and reconstruct the road network, calculate the average slope of each preset length as the slope value of the current preset length, calculate the engine power of the current preset length according to the slope value of the current preset length and the current vehicle speed, and use the engine power and ambient temperature as input parameters of the fuzzy control algorithm to calculate the output target water temperature; according to the difference between the current water temperature and the target water temperature, the PID control algorithm is used to calculate the target fan speed;

[0025] The electronically controlled silicone oil fan execution module is used to execute the calculated target fan speed and realize the target fan speed response.

[0026] The present invention estimates the driving power of the whole vehicle based on the slope of the terrain ahead, and dynamically adjusts the target water temperature through a fuzzy control method in combination with the current ambient temperature, thereby improving the control adaptability of different working conditions, reducing direct connection of the fan, reducing fan power consumption, and improving the fuel economy of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of a predictive fan control system based on fuzzy hierarchical control according to the present invention.

[0028] Figure 2 It is a curve diagram of the target water temperature control fitting method of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] A predictive fan control method based on fuzzy hierarchical control comprises the following steps:

[0031] The CAN signal is sent to the VCU controller via the vehicle CAN bus to provide basic vehicle information, including coolant temperature, vehicle speed, and ambient temperature.

[0032] The map module sends the vehicle's current position and raw data of the slope ahead to the VCU controller. The raw data of the slope ahead is a standard message that complies with the ADSIS protocol, specifically involving the path index and offset in the profile short message.

[0033] The VCU controller receives basic vehicle information, raw data of the slope ahead, and the vehicle's current location information and reconstructs the road network, calculating the average slope every 300 meters as the slope value for the next 300 meters.

[0034] Calculate the engine power for the next 300m based on the slope value for the next 300m and the current vehicle speed;

[0035] The calculation formula of the engine power is:

[0036]

[0037] Among them, m is the vehicle load, g is the gravity acceleration, f is the rolling damping coefficient, α is the road slope, C D is the air resistance coefficient, A is the windward area, u a is the driving speed.

[0038] The target water temperature is calculated by applying the fuzzy control algorithm: the engine power and the ambient temperature are used as the input parameters of the fuzzy control algorithm to calculate the output target water temperature; fuzzy rules are formulated based on the calibration experience, and the fuzzy control system quantifies the target water temperature according to the formulated fuzzy rules and membership functions.

[0039] Since the target water temperature calculation cycle is not consistent with the actual control cycle, in order to minimize the fan control speed fluctuation, the target water temperature is fitted and controlled by a quadratic function according to the trend of water temperature change, such as Figure 2 As shown, when the target water temperature rises, it is fast at first and then slow, and when the target water temperature drops, it is slow at first and then fast, so as to conform to the actual water temperature change trend as much as possible and reduce the fan power consumption.

[0040] Set the target water temperature calculation cycle to T, the target water temperature control cycle to t, the target water temperature of the previous calculation cycle to tem1, and the template water temperature of the next calculation cycle to tem2;

[0041] When tem1>tem2, assuming tem1-tem2=s, then the target water temperature is sent at time t When tem1<tem2, assuming tem2-tem1=s, then the target water temperature is sent at time t

[0042] According to the difference between the current water temperature and the target water temperature, the PID control algorithm is applied to calculate the target fan speed, the integral separation coefficient is set to adjust the integral action strength, the integral saturation limit threshold is set to solve the integral saturation problem, and a feedforward table with ambient temperature and predicted power as influencing factors is added. The PID control is corrected using feedforward control to improve the system response speed.

[0043] like Figure 1 As shown, a predictive fan control system based on fuzzy hierarchical control includes:

[0044] CAN bus, used to send CAN signals to the VCU controller to provide basic vehicle information;

[0045] Map module, used to send the original data information of the vehicle's current position and the slope ahead to the VCU controller;

[0046] The VCU controller has a built-in predictive fan control package, which is used to receive the original data information of the basic information of the vehicle, the current position and the slope ahead and reconstruct the road network, calculate the average slope of each preset length as the slope value of the current preset length, calculate the engine power of the current preset length according to the slope value of the current preset length and the current vehicle speed, and use the engine power and ambient temperature as input parameters of the fuzzy control algorithm to calculate the output target water temperature; according to the difference between the current water temperature and the target water temperature, the PID control algorithm is used to calculate the target fan speed;

[0047] The electronically controlled silicone oil fan execution module is used to execute the calculated target fan speed and realize the target fan speed response.

[0048] The present invention can predict the road conditions ahead in real time, and dynamically adjust the target water temperature by applying fuzzy control methods in combination with the ambient temperature, so as to avoid unnecessary fan intervention as much as possible, reduce fan power consumption, and improve fuel saving rate. Compared with the traditional single calibration curve control, the present invention has stronger control adaptability to different working conditions. The present invention can reduce unnecessary fan speed response through fuzzy rule calibration, and can minimize fan power consumption without overheating, save fuel consumption, and improve the economic benefits of users.

[0049] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A predictive fan control method based on fuzzy hierarchical control, characterized in that: The steps include: Send CAN signals to the VCU controller via the vehicle CAN bus to provide basic vehicle information; Send the original data information of the vehicle's current position and the slope ahead to the VCU controller through the map module; The VCU controller receives basic vehicle information, raw data information of the front slope and the current position information of the vehicle and reconstructs the road network, and calculates the average slope of each preset length as the slope value of the current preset length; Calculate the engine power of the current preset length according to the slope value of the current preset length and the current vehicle speed; The engine power and ambient temperature are used as input parameters of the fuzzy control algorithm to calculate the output target water temperature; According to the difference between the current water temperature and the target water temperature, the PID control algorithm is applied to calculate the target fan speed.

2. The predictive fan control method based on fuzzy hierarchical control according to claim 1, characterized in that: The basic vehicle information includes coolant temperature, vehicle speed and ambient temperature.

3. The predictive fan control method based on fuzzy hierarchical control according to claim 1, characterized in that: The preset length is 300m.

4. The predictive fan control method for commercial vehicles based on fuzzy hierarchical control according to claim 1, characterized in that: The calculation formula of the engine power is: Among them, m is the vehicle load, g is the gravity acceleration, f is the rolling damping coefficient, α is the road slope, C D is the air resistance coefficient, A is the windward area, u a is the driving speed.

5. The predictive fan control method based on fuzzy hierarchical control according to claim 1, characterized in that: The fuzzy control algorithm is used to calculate the target water temperature and a quadratic function is used for fitting control to adapt to the trend of water temperature changes.

6. The predictive fan control method based on fuzzy hierarchical control according to claim 5, characterized in that: Set the target water temperature calculation cycle to T, the target water temperature control cycle to t, the target water temperature of the previous calculation cycle to tem1, and the template water temperature of the next calculation cycle to tem2; When tem1>tem2, assuming tem1-tem2=s, then the target water temperature is sent at time t When tem1<tem2, assuming tem2-tem1=s, then the target water temperature is sent at time t 7. The predictive fan control method based on fuzzy hierarchical control according to claim 1, characterized in that: The specific method of using PID control algorithm to calculate the target fan speed is as follows: setting the integral separation coefficient to adjust the integral action strength, setting the integral saturation limit threshold to solve the integral saturation problem, adding a feedforward table with ambient temperature and predicted power as influencing factors, and using feedforward control to correct PID control and improve the system response speed.

8. A control system using a predictive fan control method based on fuzzy hierarchical control as claimed in any one of claims 1 to 7, characterized in that: include: CAN bus, used to send CAN signals to the VCU controller to provide basic vehicle information; Map module, used to send the original data information of the vehicle's current position and the slope ahead to the VCU controller; The VCU controller has a built-in predictive fan control package, which is used to receive the original data information of the basic information of the vehicle, the current position and the slope ahead and reconstruct the road network, calculate the average slope of each preset length as the slope value of the current preset length, calculate the engine power of the current preset length according to the slope value of the current preset length and the current vehicle speed, and use the engine power and ambient temperature as the input parameters of the fuzzy control algorithm to calculate the output target water temperature; According to the difference between the current water temperature and the target water temperature, the PID control algorithm is applied to calculate the target fan speed; The electronically controlled silicone oil fan execution module is used to execute the calculated target fan speed and realize the target fan speed response.

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