A method for controlling an electronically controlled thermostat in a commercial vehicle

Abstract

This invention discloses a control method for an electronically controlled thermostat in commercial vehicles, relating to the field of thermostat technology, and solving the technical problem that there is currently no universal control method for electronically controlled thermostats. The method involves acquiring the engine's required thermostat opening, retarder parameters, retarder status, coolant temperature sensor operating status, engine operating status, and engine operating parameters. Based on the engine's required thermostat opening, retarder parameters, and retarder status, the required thermostat opening for the retarder is obtained. The required opening of the electronically controlled thermostat is obtained through the retarder's required thermostat opening, coolant temperature sensor operating status, and engine operating status. The heating duty cycle of the electronically controlled thermostat is obtained through the required thermostat opening and engine operating parameters. The electronically controlled thermostat is then controlled using the required thermostat opening and the heating duty cycle. This invention effectively improves the engine cooling system's ability to regulate coolant temperature, enhancing reliability and economy.

Description

Technical Field

[0001] This invention relates to the field of thermostat technology, and more specifically, to a control method for an electronically controlled thermostat in a commercial vehicle. Background Technology

[0002] Electronically controlled diesel engines are now widely used, and their performance in many aspects is superior to traditional mechanical oil pump engines. Most existing electronically controlled diesel engines use paraffin thermostats, which work by controlling the opening of the large and small circulation valves through the thermal expansion and contraction of paraffin. However, using paraffin thermostats leads to the following disadvantages: the opening of the paraffin thermostat is only passively affected by the engine coolant temperature, and there is a lag, resulting in poor local cooling and mechanical wear of the engine; in high-altitude areas, due to low atmospheric pressure, the boiling point of the engine coolant decreases, while the thermal expansion and contraction characteristics of the paraffin thermostat remain almost unchanged, making the engine coolant prone to boiling over and causing cavitation in the engine water pump.

[0003] In recent years, in order to avoid the shortcomings of traditional paraffin thermostats, domestic commercial vehicles have been gradually developing electric heating thermostats and electronic thermostats. However, there is currently no universal control method for electric heating thermostats and electronic thermostats. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a control method for an electronically controlled thermostat in commercial vehicles, which addresses the shortcomings of the existing technology and solves the technical problem that there is currently no universal control method for electronically controlled thermostats.

[0005] The present invention discloses a method for controlling an electronically controlled thermostat in a commercial vehicle. The method involves acquiring the engine's required thermostat opening, retarder parameters, retarder status, coolant temperature sensor operating status, engine operating status, and engine running parameters. Based on the engine's required thermostat opening, retarder parameters, and retarder status, the required thermostat opening for the retarder is obtained. The required opening of the electronically controlled thermostat is obtained using the retarder's required thermostat opening, coolant temperature sensor operating status, and engine operating status. The heating duty cycle of the electronically controlled thermostat is obtained using the required thermostat opening and engine running parameters. The electronically controlled thermostat is then controlled using the required thermostat opening and the heating duty cycle.

[0006] To further improve the method, the method for obtaining the required engine thermostat opening is as follows: obtain the basic required engine thermostat opening, environmental parameters, and heater status; correct the basic required engine thermostat opening using the environmental parameters to obtain the required thermostat opening; obtain the required heater opening using the heater status and the required thermostat opening; and obtain the required engine thermostat opening based on the required heater opening and the engine starting process.

[0007] Furthermore, the method for obtaining the required basic opening of the engine thermostat is as follows: a cycle is set, and the state of the basic pulse spectrum selection switch, engine coolant temperature, and actual engine torque of the engine operating parameters are obtained within the cycle. When the basic pulse spectrum selection switch is in the closed state, the required basic opening of the engine thermostat is calibrated according to the engine coolant temperature and actual engine torque.

[0008] When the basic pulse spectrum selection switch is in the open state, the engine coolant temperature change rate is acquired. A first opening value and a second opening value are obtained by calibrating the engine coolant temperature and the actual engine torque. When the engine coolant temperature change rate is less than a preset temperature change rate threshold, the engine demand thermostat basic opening is the first opening value; when the engine coolant temperature change rate is greater than the temperature change rate threshold, the engine demand thermostat basic opening is the second opening value; when the engine coolant temperature change rate is equal to the temperature change rate threshold, the engine demand thermostat basic opening is the engine demand thermostat basic opening of the previous cycle.

[0009] Furthermore, the method for obtaining the required thermostat opening by correcting the basic opening of the engine thermostat through the environmental parameters is as follows: obtain the current position slope, environmental pressure and environmental temperature in the environmental parameters, and calibrate the first thermostat opening correction value by using the current position slope and the preset slope-opening curve.

[0010] The correction value for the second thermostat opening is obtained by calibrating the engine water temperature and engine water temperature change rate.

[0011] Obtain the current vehicle speed, and use the current vehicle speed and engine coolant temperature calibration to obtain the third thermostat opening correction value;

[0012] The fourth thermostat opening correction value is obtained through the environmental pressure and environmental temperature calibration.

[0013] The required thermostat opening is obtained by adding the engine's required thermostat opening value, the first thermostat opening correction value, the second thermostat opening correction value, the third thermostat opening correction value, and the fourth thermostat opening correction value.

[0014] Furthermore, the method for obtaining the required thermostat opening based on the heating status and the required thermostat opening is as follows: when the heating status is on, the required thermostat opening is calibrated using the engine coolant temperature and a preset coolant temperature-opening curve; when the heating status is off, the required thermostat opening is the required thermostat opening.

[0015] Furthermore, the method for obtaining the required engine thermostat opening based on the required heating thermostat opening and the engine starting process is as follows:

[0016] The engine running time after starting is obtained during the engine start-up process. When the engine running time after starting is less than or equal to a preset running time calibration value and the engine coolant temperature is greater than or equal to a preset coolant temperature calibration value, the engine required thermostat opening is equal to a preset engine required thermostat opening standard value; otherwise, the engine required thermostat opening is equal to the heater required thermostat opening.

[0017] Furthermore, the method for obtaining the required thermostat opening of the retarder based on the engine's required thermostat opening, retarder parameters, and retarder status includes,

[0018] The retarder activation state is obtained from the retarder status. When the retarder activation state is a preset first activation state value, the retarder's required thermostat opening is equal to the engine's required thermostat opening. When the retarder activation state is a preset second activation state value, the retarder temperature, retarder gear, and retarder actual torque percentage from the retarder parameters are obtained. The first retarder opening value is obtained through calibration using the retarder temperature and retarder gear. The first retarder opening value is obtained through the actual torque percentage and a preset torque... The second retarder opening value is calibrated using a torque percentage-opening curve. The required thermostat opening value of the retarder is obtained by adding the first and second retarder opening values. When the retarder is activated at a preset third activation state value, the required thermostat opening value of the retarder is obtained by calibrating the retarder temperature and the actual torque percentage of the retarder. When the retarder is activated at a preset fourth activation state value, the required thermostat opening value of the retarder is obtained by calibrating the actual torque percentage of the retarder and the retarder gear.

[0019] Furthermore, the method for obtaining the required thermostat opening of the retarder based on the engine's required thermostat opening, retarder parameters, and retarder status also includes,

[0020] When the actual torque percentage of the retarder is less than a preset torque percentage threshold, the retarder requires a thermostat opening equal to the engine requires a thermostat opening; otherwise, the required thermostat opening is obtained by calibrating the retarder temperature and the actual torque percentage of the retarder.

[0021] Furthermore, the method for obtaining the required opening degree of the electronically controlled thermostat by considering the retarder's required thermostat opening degree, the coolant temperature sensor's operating status, and the engine's operating status is as follows:

[0022] When the engine is in a stopped state, the required opening degree of the electronically controlled thermostat is the preset default opening degree required for engine shutdown.

[0023] When the engine is in a non-stop state and the coolant temperature sensor is in a fault state, the electronic thermostat needs to be opened at the preset default opening degree for coolant temperature sensor fault.

[0024] When the engine is in a non-stop operating state and the coolant temperature sensor is in a normal operating state, the required opening degree of the electronically controlled thermostat is the same as the required opening degree of the retarder thermostat.

[0025] Furthermore, the method for obtaining the heating duty cycle of the electronic thermostat is as follows: obtain the vehicle battery voltage and the engine coolant temperature from the engine operating parameters; calibrate the required heating power of the electronic thermostat using the engine coolant temperature and the required opening degree of the electronic thermostat; calibrate the power correction coefficient using the vehicle battery voltage and a preset voltage-power coefficient curve; multiply the required heating power by the correction coefficient to obtain the required heating correction power; and calibrate the heating duty cycle of the electronic thermostat using the required heating correction power and a preset power-duty cycle curve.

[0026] Beneficial effects

[0027] The advantages of this invention are:

[0028] This invention obtains the required thermostat opening of the retarder based on the engine's required thermostat opening, retarder parameters, and retarder status. It then obtains the required opening of the electronically controlled thermostat by considering the retarder's required thermostat opening, the coolant temperature sensor's operating status, and the engine's operating status. Finally, it obtains the heating duty cycle of the electronically controlled thermostat by considering the required opening and engine operating parameters. The invention controls the electronically controlled thermostat using these parameters, achieving control over both electrically heated and electronically controlled thermostats. This effectively improves the engine cooling system's ability to regulate coolant temperature, enhancing reliability and economy. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating the process of obtaining the required opening degree of the electronically controlled thermostat in the control method of the present invention.

[0030] Figure 2 This is a flowchart illustrating the process of obtaining the required basic opening degree of the engine thermostat in the control method of the present invention.

[0031] Figure 3 This is a flowchart illustrating the process of obtaining the required opening degree of the thermostat in the control method of the present invention.

[0032] Figure 4 This is a flowchart illustrating the process of obtaining the thermostat opening degree for heating demand in the control method of the present invention.

[0033] Figure 5This is a flowchart illustrating the process of obtaining the required engine thermostat opening in the control method of the present invention.

[0034] Figure 6 This is a flowchart of the control method of the present invention for obtaining the required thermostat opening degree of the retarder;

[0035] Figure 7 This is a flowchart illustrating the process of obtaining the heating duty cycle of the electric heating thermostat in the control method of the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0037] See Figures 1-7 The present invention discloses a method for controlling an electronically controlled thermostat in a commercial vehicle. The method includes the following steps: Step 1: acquiring the required thermostat opening degree of the engine, retarder parameters and retarder status, coolant temperature sensor working status, engine working status and engine operating parameters.

[0038] The method for obtaining the required thermostat opening of the engine is as follows: obtain the basic required thermostat opening of the engine, environmental parameters, and heating status; correct the basic required thermostat opening of the engine using the environmental parameters to obtain the required thermostat opening; obtain the required heating thermostat opening using the heating status and the required thermostat opening; and obtain the required engine thermostat opening based on the required heating thermostat opening and the engine starting process.

[0039] like Figure 2 As shown, the method for obtaining the engine's required thermostat base opening is as follows: different calculation methods for the engine's required thermostat base opening are selected by the state of the base pulse spectrum selection switch. A cycle is set, and the state of the base pulse spectrum selection switch, engine coolant temperature, and actual engine torque are obtained within the cycle. When the base pulse spectrum selection switch is in the closed state, the engine's required thermostat base opening is obtained by looking up the pulse spectrum (MAP1) based on the engine coolant temperature and actual engine torque after filtering.

[0040] When the basic pulse spectrum selection switch is on, the engine coolant temperature change rate is acquired. The first and second opening values ​​are obtained through calibration using the engine coolant temperature and actual engine torque. The first opening value is calibrated using the second torque pulse spectrum (MAP2), and the second opening value is calibrated using the third torque pulse spectrum (MAP3). When the engine coolant temperature change rate is less than a preset temperature change rate threshold, the engine requires the thermostat's basic opening value to be the first opening value. When the engine coolant temperature change rate is greater than the temperature change rate threshold, the engine requires the thermostat's basic opening value to be the second opening value. When the engine coolant temperature change rate equals the temperature change rate threshold, the engine requires the thermostat's basic opening value to be the same as the previous cycle's required thermostat basic opening value, i.e., hysteresis, maintaining the value of the previous cycle and keeping the system stable.

[0041] like Figure 3 As shown, the method for obtaining the required thermostat opening by correcting the basic opening of the engine thermostat through environmental parameters is as follows: obtain the current position slope, environmental pressure and environmental temperature in the environmental parameters, and calibrate the first thermostat opening correction value by using the current position slope and the preset slope-opening curve.

[0042] The correction value for the second thermostat opening is obtained by calibrating the engine coolant temperature and engine coolant temperature change rate.

[0043] Obtain the current vehicle speed, and use the current vehicle speed and engine coolant temperature calibration to obtain the correction value for the third thermostat opening;

[0044] The correction value for the opening degree of the fourth thermostat was obtained by calibrating with ambient pressure and ambient temperature.

[0045] The required thermostat opening is obtained by adding the engine's required thermostat opening value, the first thermostat opening correction value, the second thermostat opening correction value, the third thermostat opening correction value, and the fourth thermostat opening correction value.

[0046] like Figure 4 As shown, the method for obtaining the required thermostat opening for heating by means of the heating status and the required thermostat opening is as follows: when the heating status is on, the required thermostat opening for heating is obtained by calibrating the engine coolant temperature and the preset coolant temperature-opening curve; when the heating status is off, the required thermostat opening for heating is the required thermostat opening.

[0047] The heating system is turned on or off based on the heating status signal, engine coolant temperature, and ambient temperature. The heating system is considered on only when the heating status signal is positive, the engine coolant temperature is greater than the preset first standard temperature, and the ambient temperature is greater than the preset standard temperature; otherwise, the heating system is considered off.

[0048] like Figure 5As shown, the method for obtaining the required engine thermostat opening based on the required heating thermostat opening and the engine starting process is as follows:

[0049] The engine starts and runs for a period of time. When the engine starts and runs for a period of time less than or equal to the preset running time calibration value and the engine coolant temperature is greater than or equal to the preset coolant temperature calibration value, the engine requires thermostat opening equal to the preset engine requires thermostat opening standard value; otherwise, the engine requires thermostat opening equal to the heater requires thermostat opening.

[0050] Step Two: The required retarder thermostat opening is obtained based on the engine's required thermostat opening, retarder parameters, and retarder status. Different calculation methods for the required retarder thermostat opening are selected via the function selection calibration switch. The base required retarder thermostat opening is corrected by engine speed and vehicle gear calibration, and then processed by the Ramp (ramp-based) module to obtain the required retarder thermostat opening. The rising and falling rates of the Ramp module are calibrated separately using engine speed and engine coolant temperature.

[0051] like Figure 6 As shown, the calculation method for the required thermostat opening of the first type of retarder is as follows:

[0052] The retarder activation state is obtained from the retarder status. When the retarder activation state is a preset first activation state value, the required thermostat opening of the retarder is equal to the required thermostat opening of the engine. When the retarder activation state is a preset second activation state value, the retarder temperature, retarder gear, and actual torque percentage of the retarder parameters are obtained. The first retarder opening value is obtained by calibrating the retarder temperature and retarder gear. The second retarder opening value is calibrated by the actual torque percentage of the retarder and a preset torque percentage-opening curve. The first and second retarder opening values ​​are added together to obtain the required thermostat opening of the retarder. When the retarder activation state is a preset third activation state value, the required thermostat opening of the retarder is obtained by calibrating the retarder temperature and actual torque percentage of the retarder. When the retarder activation state is a preset fourth activation state value, the required thermostat opening of the retarder is obtained by calibrating the actual torque percentage of the retarder and the retarder gear.

[0053] In this embodiment, the first activation state value is 0, which indicates that the retarder braking is not activated; the second activation state value is 1; the third activation state value is 2; and the fourth activation state value is 3.

[0054] like Figure 7 As shown, the calculation method for the required thermostat opening degree of the second type of retarder is as follows:

[0055] When the actual torque percentage of the retarder is less than the preset torque percentage threshold, the retarder requires the thermostat opening to be equal to the engine requires the thermostat opening; otherwise, the retarder requires the thermostat opening to be determined by calibrating the retarder temperature and the actual torque percentage of the retarder.

[0056] The required opening degree of the electronically controlled thermostat is obtained by considering the retarder's required thermostat opening degree, the working status of the coolant temperature sensor, and the engine's working status.

[0057] The retarder temperature is either the retarder water temperature or the retarder oil temperature, and the retarder temperature is selected by a retarder temperature switch.

[0058] Step 3: The method for obtaining the required opening degree of the electronically controlled thermostat by considering the retarder's required thermostat opening degree, the working status of the coolant temperature sensor, and the engine's working status is as follows:

[0059] When the engine is in a stopped state, the electronic thermostat requires an opening of the preset default opening for engine shutdown.

[0060] When the engine is not stopped and the coolant temperature sensor is in a fault state, the electronic thermostat needs to be opened at the preset default opening degree when the coolant temperature sensor is faulty.

[0061] When the engine is not stopped and the coolant temperature sensor is in normal working condition, the required opening degree of the electronic thermostat is the same as that required by the retarder.

[0062] Step 4: Obtain the heating duty cycle of the electronic thermostat by analyzing the required opening degree of the electronic thermostat and the engine operating parameters. Control the electronic thermostat using this required opening degree and heating duty cycle. This achieves control over both the electrically heated and electronic thermostats, effectively improving the engine cooling system's ability to regulate coolant temperature, thus enhancing reliability and fuel economy.

[0063] The method for obtaining the heating duty cycle of the electronic thermostat is as follows: obtain the vehicle battery voltage and engine coolant temperature from the engine operating parameters; calibrate the required heating power of the electronic thermostat by using the engine coolant temperature and the required opening degree of the electronic thermostat; calibrate the power correction coefficient by using the vehicle battery voltage and the preset voltage-power coefficient curve; multiply the required heating power by the correction coefficient to obtain the required heating correction power; and calibrate the heating duty cycle of the electronic thermostat by using the required heating correction power and the preset power-duty cycle curve.

[0064] Select either an electronic thermostat or an electrically heated thermostat using the thermostat type selection switch.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A method for controlling an electronically controlled thermostat in a commercial vehicle, characterized in that, The system acquires the engine's required thermostat opening, retarder parameters, retarder status, coolant temperature sensor operating status, engine operating status, and engine running parameters. Based on the engine's required thermostat opening, retarder parameters, and retarder status, it obtains the required thermostat opening for the retarder. Based on the retarder's required thermostat opening, coolant temperature sensor operating status, and engine operating status, it obtains the required opening of the electronically controlled thermostat. Based on the required opening of the electronically controlled thermostat and the engine running parameters, it obtains the heating duty cycle of the electronically controlled thermostat. Based on the required opening of the electronically controlled thermostat and the heating duty cycle of the electronically controlled thermostat, it controls the electronically controlled thermostat. The method for obtaining the required thermostat opening of the retarder based on the engine's required thermostat opening, retarder parameters, and retarder status includes: Obtain the retarder activation state in the retarder state. When the retarder activation state is a preset first activation state value, the retarder requires thermostat opening degree equal to the engine requires thermostat opening degree. When the retarder is activated at a preset second activation state value, the retarder temperature, retarder gear, and actual torque percentage of the retarder parameters are obtained. The first retarder opening value is obtained by calibrating the retarder temperature and retarder gear. The second retarder opening value is calibrated by the actual torque percentage of the retarder and a preset torque percentage-opening curve. The first retarder opening value and the second retarder opening value are added together to obtain the required thermostat opening of the retarder. When the retarder is activated at a preset third activation state value, the required thermostat opening of the retarder is obtained by calibrating the retarder temperature and the actual torque percentage of the retarder; when the retarder is activated at a preset fourth activation state value, the required thermostat opening of the retarder is obtained by calibrating the actual torque percentage of the retarder and the retarder gear. The method for obtaining the required thermostat opening of the retarder based on the engine's required thermostat opening, retarder parameters, and retarder status also includes... When the actual torque percentage of the retarder is less than the preset torque percentage threshold, the retarder requires the thermostat opening to be equal to the engine requires the thermostat opening. Conversely, the required thermostat opening of the retarder is obtained by calibrating the retarder temperature and the actual torque percentage of the retarder. The method for obtaining the required opening degree of the electronically controlled thermostat by considering the retarder's required thermostat opening degree, the operating status of the coolant temperature sensor, and the engine's operating status is as follows: When the engine is in a stopped state, the required opening degree of the electronically controlled thermostat is the preset default opening degree required for engine shutdown. When the engine is in a non-stop state and the coolant temperature sensor is in a fault state, the electronic thermostat needs to be opened at the preset default opening degree for coolant temperature sensor fault. When the engine is in a non-stop operating state and the coolant temperature sensor is in a normal operating state, the required opening degree of the electronically controlled thermostat is the same as the required opening degree of the retarder thermostat.

2. The method for controlling an electronically controlled thermostat in a commercial vehicle according to claim 1, characterized in that, The method for obtaining the required thermostat opening of the engine is as follows: obtain the basic required thermostat opening of the engine, environmental parameters, and heating status; correct the basic required thermostat opening of the engine using the environmental parameters to obtain the required thermostat opening; obtain the required heating thermostat opening using the heating status and the required thermostat opening; and obtain the required engine thermostat opening based on the required heating thermostat opening and the engine starting process.

3. The method for controlling an electronically controlled thermostat in a commercial vehicle according to claim 2, characterized in that, The method for obtaining the required basic opening of the engine thermostat is as follows: a cycle is set, and the state of the basic pulse spectrum selection switch, engine coolant temperature, and actual engine torque of the engine operating parameters are obtained within the cycle. When the basic pulse spectrum selection switch is in the closed state, the required basic opening of the engine thermostat is calibrated according to the engine coolant temperature and actual engine torque. When the basic pulse spectrum selection switch is in the open state, the engine coolant temperature change rate is acquired. A first opening value and a second opening value are obtained by calibrating the engine coolant temperature and the actual engine torque. When the engine coolant temperature change rate is less than a preset temperature change rate threshold, the engine demand thermostat basic opening is the first opening value; when the engine coolant temperature change rate is greater than the temperature change rate threshold, the engine demand thermostat basic opening is the second opening value; when the engine coolant temperature change rate is equal to the temperature change rate threshold, the engine demand thermostat basic opening is the engine demand thermostat basic opening of the previous cycle.

4. The method for controlling an electronically controlled thermostat in a commercial vehicle according to claim 3, characterized in that, The method for obtaining the required thermostat opening by correcting the basic opening of the engine thermostat using the environmental parameters is as follows: obtain the current position slope, environmental pressure and environmental temperature from the environmental parameters, and calibrate the first thermostat opening correction value by using the current position slope and the preset slope-opening curve. The correction value for the second thermostat opening is obtained by calibrating the engine water temperature and engine water temperature change rate. Obtain the current vehicle speed, and use the current vehicle speed and engine coolant temperature calibration to obtain the third thermostat opening correction value; The fourth thermostat opening correction value is obtained through the environmental pressure and environmental temperature calibration. The required thermostat opening is obtained by adding the engine's required thermostat opening value, the first thermostat opening correction value, the second thermostat opening correction value, the third thermostat opening correction value, and the fourth thermostat opening correction value.

5. The method for controlling an electronically controlled thermostat in a commercial vehicle according to claim 4, characterized in that, The method for obtaining the required thermostat opening based on the heating status and the required thermostat opening is as follows: when the heating status is on, the required thermostat opening is calibrated using the engine coolant temperature and a preset coolant temperature-opening curve; when the heating status is off, the required thermostat opening is the required thermostat opening.

6. The method for controlling an electronically controlled thermostat in a commercial vehicle according to claim 5, characterized in that, The method for determining the required engine thermostat opening based on the required heater opening and the engine start-up process is as follows: The engine running time after starting is obtained during the engine start-up process. When the engine running time after starting is less than or equal to a preset running time calibration value and the engine water temperature is greater than or equal to a preset water temperature calibration value, the engine required thermostat opening is equal to a preset engine required thermostat opening standard value. Conversely, the required thermostat opening for the engine is equal to the required thermostat opening for the heater.

7. The method for controlling an electronically controlled thermostat in a commercial vehicle according to claim 1, characterized in that, The method for obtaining the heating duty cycle of the electronic thermostat is as follows: obtain the vehicle battery voltage and the engine coolant temperature from the engine operating parameters; calibrate the required heating power of the electronic thermostat using the engine coolant temperature and the required opening degree of the electronic thermostat; calibrate the power correction coefficient using the vehicle battery voltage and a preset voltage-power coefficient curve; multiply the required heating power by the correction coefficient to obtain the required heating correction power; and calibrate the heating duty cycle of the electronic thermostat using the required heating correction power and a preset power-duty cycle curve.

Images