A method and system for heating control of a diesel engine air intake grille

Abstract

The present application relates to the field of electrically controlled diesel engine power control, and discloses a diesel engine air intake grille heating control method and system, wherein according to information such as air intake temperature, coolant temperature and engine speed when the diesel engine starts, the diesel engine air intake grille heating process is divided into a preparation stage, a preheating stage and a starting stage, corresponding heating control methods are adopted in different stages, the heating duration and output power control of the air intake grille heater are performed by controlling the pulse width modulation signal of grille heating, the air intake grille heating effect control can be realized without changing the hardware product, the cost is low, and the diesel engine air intake grille can be precisely heated to achieve a good heating effect.

Description

Technical Field

[0001] The invention relates to the field of power control of electronically controlled diesel engines and discloses a method and system for controlling heating of an air intake grille of a diesel engine. Background Art

[0002] In low-temperature environments, diesel engine lubricant viscosity increases, fluidity deteriorates, frictional resistance increases, battery activity decreases, capacity decreases, and starting torque also decreases. Combined with the low mixture and combustion chamber ambient temperatures, diesel engines struggle to start and are prone to stalling after successful starts. Common measures to improve cold-start characteristics include modifying engine structural parameters, optimizing injection strategies, using alternative fuels, and adding intake air preheating devices.

[0003] Most of the above optimization methods require adjustments to the layout structure of the diesel engine, and require the addition or modification of hardware products, resulting in high optimization costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a diesel engine air intake grille heating control method and system, which can realize the precise heating of the diesel engine air intake grille and achieve better heating effect; and the air intake grille heating effect control can be realized without changing the hardware products, and the cost is low.

[0005] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0006] A diesel engine air intake grille heating control method, comprising:

[0007] Starting a controller of the diesel engine, collecting an intake air temperature and a coolant temperature of the diesel engine when the controller is started, and calculating a preheating temperature based on the intake air temperature and the coolant temperature;

[0008] Starting from the start of the diesel engine controller, the diesel engine air intake grille heating process is divided into a preparation phase, a preheating phase, and a starting phase according to the controller operation time and the diesel engine speed; wherein the preparation phase is the time period from the start of the diesel engine controller to the preset delay time, the preheating phase is the time period from the preset delay time to the time when the diesel engine speed is less than a first preset speed, and the starting phase is the time period when the diesel engine speed is greater than or equal to the first preset speed and less than a second preset speed;

[0009] A pulse width modulator is used for grid heating control, where:

[0010] When the diesel engine air intake grille heating state is in the preparation stage, the grid heating pulse width modulation signal output duty cycle of the pulse width modulator is 0%;

[0011] When the diesel engine air intake grille heating state enters the preheating stage, the pulse width modulator performs grille heating control according to a preset preheating time threshold, wherein: if the preheating stage duration is less than or equal to the preset preheating time threshold, the grille heating pulse width modulation signal output duty cycle is 100%; if the preheating stage duration exceeds the preset preheating time threshold, then after the preheating time threshold, the grille heating pulse width modulation signal output duty cycle is 0%;

[0012] When the diesel engine air intake grille heating state enters the starting phase, if the preheating temperature is less than the first temperature threshold and the starting phase is maintained within 10 seconds, the grid heating pulse width modulation signal output duty cycle is 100%, otherwise the grid heating pulse width modulation signal output duty cycle is 0%;

[0013] When all stages of heating are completed or the coolant temperature is higher than the third temperature threshold or the diesel engine is in a steady state, the air intake grille heating is terminated.

[0014] Furthermore, the preheating temperature is based on T s =k·T co +(1-k)T ch The analysis results show that T s is the preheating temperature, k is the temperature weight coefficient, the value range of k is 0~1, T co is the coolant temperature, T ch is the intake air temperature.

[0015] Furthermore, the preset preheating time threshold is based on The analysis results show that t p is the warm-up time threshold, T s is the preheating temperature, and w is the heating rate of the air intake grille when the duty cycle of the grille heating pulse width modulation signal output is 100%.

[0016] Furthermore, the system further includes a post-heating stage, which is a period of time when the speed of the diesel engine is greater than or equal to a second preset speed; a heating method in the post-heating stage includes: dividing the preheating temperature range into 4 to 6 post-heating levels according to a temperature gradient based on a preset preheating temperature lower limit value and a preheating temperature upper limit value range;

[0017] The heating mode of each post-heating level is divided into 4 to 6 heating steps, and a grid heating pulse width modulation signal corresponding to each heating step is set according to each heating step; wherein the grid heating pulse width modulation signal of each heating step includes a heating duration and a pulse width modulation signal output duty cycle corresponding to the heating duration;

[0018] According to the preheating temperature obtained by analysis, the afterheating level of the preheating temperature is determined, and the air intake grille is heated according to the grille heating pulse width modulation signal of each heating step under the corresponding afterheating level.

[0019] To achieve the above technical effects, the present invention further provides a diesel engine air intake grille heating control system, which is used to implement the diesel engine air intake grille heating control method, comprising:

[0020] a data processing module, configured to collect the intake air temperature and coolant temperature of the diesel engine when the controller is started, and calculate the preheating temperature based on the intake air temperature and the coolant temperature;

[0021] a stage division module, configured to divide the diesel engine air intake grille heating process into a preparation stage, a preheating stage, and a starting stage, starting from the start of the diesel engine controller and based on the controller operation time and the diesel engine speed; wherein the preparation stage is a period from the start of the diesel engine controller to a preset delay time, the preheating stage is a period from the preset delay time to the time when the diesel engine speed is less than a first preset speed, and the starting stage is a period from the time when the diesel engine speed is greater than or equal to the first preset speed and less than a second preset speed;

[0022] A heating control module uses a pulse width modulator to control grille heating and terminates grille heating when all heating stages are completed, the coolant temperature is higher than a third temperature threshold, or the diesel engine is in a steady state; wherein the heating control module includes:

[0023] a preparation stage control unit, configured to, after the diesel engine air intake grille heating state is in the preparation stage, use a pulse width modulator to control the grille heating pulse width modulation signal output duty cycle to be 0%;

[0024] a preheating stage control unit, configured to control grille heating according to a preset preheating time threshold after the diesel engine air intake grille enters the preheating stage, wherein: if the preheating stage duration is less than or equal to the preset preheating time threshold, the grille heating pulse width modulation signal output duty cycle is 100%; if the preheating stage duration exceeds the preset preheating time threshold, then after the preheating time threshold, the grille heating pulse width modulation signal output duty cycle is 0%;

[0025] The starting phase control unit is used to, after the diesel engine air intake grille enters the starting phase in the heating state, if the preheating temperature is less than the first temperature threshold and the starting phase is maintained within 10 seconds, the grille heating pulse width modulation signal output duty cycle is 100%, otherwise the grille heating pulse width modulation signal output duty cycle is 0%.

[0026] Furthermore, in the heating control module, the preheating temperature is set according to T s =k·T co +(1-k)T ch The analysis results show that T s is the preheating temperature, k is the temperature weight coefficient, the value range of k is 0~1, T co is the coolant temperature, T ch is the intake air temperature.

[0027] Furthermore, in the heating control module, the preset preheating time threshold is based on The analysis results show that t p is the warm-up time threshold, T s is the preheating temperature, and w is the heating rate of the air intake grille when the duty cycle of the grille heating pulse width modulation signal output is 100%.

[0028] Furthermore, the heating control module also includes a post-heating stage control unit, which is used to divide the preheating temperature range into 4 to 6 post-heating levels according to the temperature gradient according to the preset preheating temperature lower limit value and the preheating temperature upper limit value range within the time period when the diesel engine speed is greater than or equal to the second preset speed; and divide the heating mode of each post-heating level into 4 to 6 heating steps, and set the grille heating pulse width modulation signal corresponding to each heating step according to each heating step; wherein the grille heating pulse width modulation signal of each heating step includes the heating time and the pulse width modulation signal output duty cycle under the corresponding heating time; based on the preheating temperature obtained by analysis, determine the post-heating level where the preheating temperature is located, and heat the air intake grille according to the grille heating pulse width modulation signal of each heating step under the corresponding post-heating level.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention divides the diesel engine air intake grille heating process into a preparation stage, a preheating stage, and a starting stage according to information such as the intake air temperature, the coolant temperature, and the engine speed when the diesel engine is started, and adopts corresponding heating control methods in different stages. The heating time and output power of the air intake grille heater are controlled by controlling the grille heating pulse width modulation signal. The air intake grille heating effect can be controlled without changing the hardware product, the cost is low, and the diesel engine air intake grille can be accurately heated to achieve a better heating effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of a method for controlling heating of an air intake grille of a diesel engine in an embodiment;

[0031] Figure 2This is a structural block diagram of a diesel engine air intake grille heating control system in an embodiment;

[0032] Among them, 1. Data processing module; 2. Stage division module; 3. Heating control module; 301. Preparation stage control unit; 302. Preheating stage control unit; 303. Start-up stage control unit; 304. Post-heating stage control unit. DETAILED DESCRIPTION

[0033] The present invention will be described in further detail below with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0034] Example

[0035] See also Figure 1-Figure 2 , a diesel engine air intake grille heating control method, comprising:

[0036] Starting a controller of the diesel engine, collecting an intake air temperature and a coolant temperature of the diesel engine when the controller is started, and calculating a preheating temperature based on the intake air temperature and the coolant temperature;

[0037] Starting from the start of the diesel engine controller, the diesel engine air intake grille heating process is divided into a preparation phase, a preheating phase, and a starting phase according to the controller operation time and the diesel engine speed; wherein the preparation phase is the time period from the start of the diesel engine controller to the preset delay time, the preheating phase is the time period from the preset delay time to the time when the diesel engine speed is less than a first preset speed, and the starting phase is the time period when the diesel engine speed is greater than or equal to the first preset speed and less than a second preset speed;

[0038] A pulse width modulator is used for grid heating control, where:

[0039] When the diesel engine air intake grille heating state is in the preparation stage, the grid heating pulse width modulation signal output duty cycle of the pulse width modulator is 0%;

[0040] When the diesel engine air intake grille heating state enters the preheating stage, the pulse width modulator performs grille heating control according to a preset preheating time threshold, wherein: if the preheating stage duration is less than or equal to the preset preheating time threshold, the grille heating pulse width modulation signal output duty cycle is 100%; if the preheating stage duration exceeds the preset preheating time threshold, then after the preheating time threshold, the grille heating pulse width modulation signal output duty cycle is 0%;

[0041] When the diesel engine air intake grille heating state enters the starting phase, if the preheating temperature is less than the first temperature threshold and the starting phase is maintained within 10 seconds, the grid heating pulse width modulation signal output duty cycle is 100%, otherwise the grid heating pulse width modulation signal output duty cycle is 0%;

[0042] When all stages of heating are completed or the coolant temperature is higher than the third temperature threshold or the diesel engine is in a steady state, the air intake grille heating is terminated.

[0043] In this embodiment, the diesel engine air intake grille heating process is divided into a preparation stage, a preheating stage, and a starting stage according to information such as the intake air temperature, coolant temperature, and engine speed when the diesel engine is started. Corresponding heating control methods are adopted in different stages. The heating time and output power of the air intake grille heater are controlled by controlling the grille heating pulse width modulation signal. The air intake grille heating effect control can be achieved without changing the hardware product. The cost is low, and the diesel engine air intake grille can be accurately heated to achieve a better heating effect.

[0044] Based on the same inventive concept, this embodiment also provides a diesel engine air intake grille heating control system, comprising:

[0045] Data processing module 1, used to collect the intake air temperature and coolant temperature of the diesel engine when the controller is started, and calculate the preheating temperature based on the intake air temperature and coolant temperature;

[0046] a stage division module 2 for dividing the diesel engine air intake grille heating process into a preparation stage, a preheating stage, and a starting stage, starting from the start of the diesel engine controller and based on the controller operation time and the diesel engine speed; wherein the preparation stage is a period from the start of the diesel engine controller to a preset delay time, the preheating stage is a period from the preset delay time to the time when the diesel engine speed is less than a first preset speed, and the starting stage is a period from the time when the diesel engine speed is greater than or equal to the first preset speed and less than a second preset speed;

[0047] The heating control module 3 uses a pulse width modulator to control grille heating and terminates grille heating when all heating stages are completed, the coolant temperature is higher than a third temperature threshold, or the diesel engine is in a steady state. The heating control module 3 includes:

[0048] The preparation stage control unit 301 is used to control the duty cycle of the grid heating pulse width modulation signal output to be 0% by using a pulse width modulator after the diesel engine intake grille heating state is in the preparation stage;

[0049] A preheating stage control unit 302 is configured to control grille heating according to a preset preheating duration threshold after the diesel engine air intake grille enters the preheating stage, wherein: if the preheating stage duration is less than or equal to the preset preheating duration threshold, the grid heating pulse width modulation signal output duty cycle is 100%; if the preheating stage duration exceeds the preset preheating duration threshold, then after the preheating duration threshold, the grid heating pulse width modulation signal output duty cycle is 0%;

[0050] The starting stage control unit 303 is used to, after the diesel engine air intake grille enters the starting stage in the heating state, if the preheating temperature is less than the first temperature threshold and the starting stage is maintained within 10s, the grille heating pulse width modulation signal output duty cycle is 100%, otherwise the grille heating pulse width modulation signal output duty cycle is 0%.

[0051] In addition, the heating control module 3 in this embodiment also includes a post-heating stage control unit 304, which is used to divide the preheating temperature range into 4 to 6 post-heating levels according to the temperature gradient within the time period when the diesel engine speed is greater than or equal to the second preset speed, according to the preset preheating temperature lower limit value and the preheating temperature upper limit value range; and divide the heating mode of each post-heating level into 4 to 6 heating steps, and set the grille heating pulse width modulation signal corresponding to each heating step according to each heating step; wherein the grille heating pulse width modulation signal of each heating step includes the heating time and the pulse width modulation signal output duty cycle under the corresponding heating time; according to the preheating temperature obtained by analysis, the post-heating level of the preheating temperature is determined, and the air intake grille is heated according to the grille heating pulse width modulation signal of each heating step under the corresponding post-heating level.

[0052] Example 2

[0053] See also Figure 1 This embodiment uses the example of heating the intake grille of a high-pressure common rail diesel engine with an electronic controller to describe the process flow of the diesel engine intake grille heating control method of the present invention in detail. The high-pressure common rail diesel engine in this embodiment is powered by an electronically controlled diesel internal combustion engine with six cylinders, a displacement of 6.7L, a maximum engine torque of 850Nm, and a rated speed of 2000r / min. The operating steps are as follows:

[0054] Step 1: Start the controller of the diesel engine, collect the intake air temperature and coolant temperature of the diesel engine when the controller is started, and calculate the preheating temperature according to the intake air temperature and the coolant temperature;

[0055] In this embodiment, the preheating temperature is based on T s =k·T co +(1-k)Tch The analysis results show that T s is the preheating temperature, k is the temperature weight coefficient, the value range of k is 0~1, T co is the coolant temperature, T ch The preheating temperature reflects the engine ambient temperature. Since both the coolant temperature and the intake air temperature can reflect the ambient temperature, the larger t is, the greater the influence of the coolant temperature on the preheating temperature; conversely, the greater the influence of the intake air temperature on the preheating temperature. t is generally around 0.5. The coolant temperature T collected in this embodiment co and intake air temperature T ch The temperature weight coefficient is k = 0.5, and the preheating temperature T is calculated. s It is -30℃.

[0056] Step 2: Starting from the start of the diesel engine controller, the diesel engine air intake grille heating process is divided into a preparation stage, a preheating stage, a starting stage and a post-heating stage according to the controller operation time and the diesel engine speed;

[0057] In this embodiment, the preset delay time is 10 seconds; the preset preheating time threshold is based on The analysis results show that t p is the warm-up time threshold, T s is the preheating temperature, w is the heating rate of the air intake grille when the duty cycle of the grid heating pulse width modulation signal output is 100%. According to the preheating temperature T calculated in step 1 s The temperature is -30°C. According to the performance of the air intake grille heater and the flow rate of the coolant, it can be obtained that when the duty cycle of the pulse width modulation signal output of the diesel engine grille heating is 100%, the heating rate of the air intake grille is about 1°C / s. Therefore, the preset preheating time threshold t is calculated. p In addition, the first preset speed is 20 rpm and the second preset speed is 500 rpm.

[0058] Therefore, the division of each stage in this embodiment is as follows:

[0059] Preparation phase: The period from when the diesel engine controller starts to the 10th second after starting;

[0060] Warm-up phase: the period from 10 seconds after the diesel engine controller is started to the time when the diesel engine speed is less than 20 rpm;

[0061] Starting phase: the period when the diesel engine speed is greater than or equal to 20 rpm and less than 500 rpm;

[0062] Post-heating stage: The diesel engine speed is greater than or equal to 500rpm until the air intake grille heating is completed.

[0063] Step 3: Use a pulse width modulator to control grid heating, where:

[0064] Step 3.1: Power on the diesel engine controller with the key signal and enter the preparation phase. Wait for the indicator light to illuminate. If the preparation phase lasts longer than the 10-second delay, the grille heating enters the preheating phase. Otherwise, it remains in the preparation phase. During the preparation phase, the grid heating pulse width modulation (PWM) output duty cycle is 0%.

[0065] Step 3.2: Starting from the 10th second after the diesel engine controller key signal is powered on, the diesel engine air intake grille heating state enters the preheating stage. After entering the preheating stage, the diesel engine speed gradually increases from 0 rpm to 20 rpm. During this process, the pulse width modulator is adjusted according to the preset preheating time threshold t p (Calculate the result according to step 2, t p If the time it takes for the speed to increase from 0 rpm to 20 rpm is less than the preheating time threshold of 30 seconds, the duty cycle of the grid heating pulse width modulation signal output is 100%; if the time it takes for the speed to increase from 0 rpm to 20 rpm is greater than or equal to the preheating time threshold of 30 seconds, then after entering the preheating stage for 30 seconds, the duty cycle of the grid heating pulse width modulation signal output is 0%;

[0066] Step 3.3: When the diesel engine speed exceeds 20 rpm, it enters the starting phase; during the starting phase, if the preheating temperature is less than the first temperature threshold and the starting phase is maintained within 10 seconds, the grid heating pulse width modulation signal output duty cycle is 100%, otherwise the grid heating pulse width modulation signal output duty cycle is 0%; in this embodiment, the first temperature threshold is -1°C.

[0067] Step 3.4: When the diesel engine speed exceeds 500 rpm, the engine enters the post-heating stage. The post-heating level is determined according to the preheating temperature, and the air intake grille is heated in a stepped heating manner according to the post-heating level. The stepped heating method includes the following specific methods:

[0068] 3.4.1 Based on the preset lower and upper limits of the preheating temperature, the preheating temperature range is divided into 4 to 6 post-heating levels according to the temperature gradient. In this embodiment, the preset lower limit of the preheating temperature is -40°C, and the preset upper limit of the preheating temperature is 5°C. The post-heating levels are divided into:

[0069] Level 0: T s <-40℃;

[0070] Level 1: -40℃≤T s <-20℃;

[0071] Level 2: -20℃≤T s <-15℃;

[0072] Level 3: -15℃≤T s <-5℃;

[0073] Level 4: -5℃≤T s <5℃;

[0074] Level 5: T s ≥5℃;

[0075] The above classification is based only on the high-pressure common rail diesel engine of the electronic controller adapted to the present embodiment. Different classification methods may be used for other types of diesel engines, such as an equal gradient classification method.

[0076] 3.4.2 The heating mode of each post-heating level is divided into 4 to 6 heating steps, and a grid heating pulse width modulation signal corresponding to each heating step is set; wherein the grid heating pulse width modulation signal for each heating step includes a heating duration and a pulse width modulation signal output duty cycle corresponding to the heating duration;

[0077] In this embodiment, the heating mode of each post-heating level is divided into four heating steps. The pulse width modulation signal output duty ratio of each heating step is shown in Table 1, and the heating time of each heating step is determined according to Table 2.

[0078] Table 1 Pulse width modulation signal output duty cycle of each heating step in the post-heating stage

[0079] Heating ladder Pulse width modulation signal output duty cycle (%) Stage 0 100 Stage 1 50 Stage 2 40 Stage 3 30

[0080] Table 2 Heating time of each heating step in the post-heating stage

[0081]

[0082] 3.4.3 Determine the post-heating level for the pre-heating temperature based on the pre-heating temperature obtained by analysis, and heat the air intake grille according to the grille heating pulse width modulation signal for each heating step corresponding to the post-heating level;

[0083] The preheating temperature T in this embodiment s The temperature is -30℃, and the corresponding post-heating level is level 1. During the level 1 heating process, the air intake grille is heated in the post-heating stage using a step heating method from Stage 0 to Stage 3. According to Tables 1 and 2, it can be seen that:

[0084] The pulse width modulation signal output duty cycle of the heating stage Stage 0 is 100%, and the heating time is 20s;

[0085] The pulse width modulation signal output duty cycle of heating stage 1 is 40%, and the heating time is 120s;

[0086] The pulse width modulation signal output duty cycle of heating stage 2 is 100%, and the heating time is 20s;

[0087] The heating time of heating stage 3 is 0.

[0088] It should be noted that, in the post-heating stage, when the step heating is completed or the post-heating temperature is higher than the second temperature threshold or the coolant temperature is higher than the third temperature threshold or the diesel engine is in a steady state, the air intake grille heating is terminated; in addition, the heating system in Tables 1 and 2 is only applicable to the diesel engine of this embodiment, and the air intake grille heating of other models of diesel engines needs to be set according to actual conditions.

[0089] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A diesel engine air intake grille heating control method, characterized in that: include: Starting a controller of the diesel engine, collecting an intake air temperature and a coolant temperature of the diesel engine when the controller is started, and calculating a preheating temperature based on the intake air temperature and the coolant temperature; Starting from the start of the diesel engine controller, the diesel engine air intake grille heating process is divided into a preparation phase, a preheating phase, and a starting phase according to the controller operation time and the diesel engine speed; wherein the preparation phase is the time period from the start of the diesel engine controller to the preset delay time, the preheating phase is the time period from the preset delay time to the time when the diesel engine speed is less than a first preset speed, and the starting phase is the time period when the diesel engine speed is greater than or equal to the first preset speed and less than a second preset speed; A pulse width modulator is used for grid heating control, where: When the diesel engine air intake grille heating state is in the preparation stage, the grid heating pulse width modulation signal output duty cycle of the pulse width modulator is 0%; When the diesel engine air intake grille heating state enters the preheating stage, the pulse width modulator performs grille heating control according to a preset preheating time threshold, wherein: if the preheating stage duration is less than or equal to the preset preheating time threshold, the grille heating pulse width modulation signal output duty cycle is 100%; if the preheating stage duration exceeds the preset preheating time threshold, then after the preheating time threshold, the grille heating pulse width modulation signal output duty cycle is 0%; When the diesel engine air intake grille heating state enters the starting phase, if the preheating temperature is less than the first temperature threshold and the starting phase is maintained within 10 seconds, the grid heating pulse width modulation signal output duty cycle is 100%, otherwise the grid heating pulse width modulation signal output duty cycle is 0%; When all stages of heating are completed or the coolant temperature is higher than the third temperature threshold or the diesel engine is in a steady state, the air intake grille heating is terminated.

2. The diesel engine air intake grille heating control method according to claim 1, characterized in that: The preheating temperature is based on T s =k·T co +(1-k)T ch The analysis results show that T s is the preheating temperature, k is the temperature weight coefficient, the value range of k is 0~1, T co is the coolant temperature, T ch is the intake air temperature.

3. The diesel engine air intake grille heating control method according to claim 2, characterized in that: The preset warm-up time threshold is based on The analysis results show that t p is the warm-up time threshold, T s is the preheating temperature, and w is the heating rate of the air intake grille when the duty cycle of the grille heating pulse width modulation signal output is 100%.

4. The diesel engine air intake grille heating control method according to claim 1, characterized in that: The system further includes a post-heating stage, which is a period of time when the speed of the diesel engine is greater than or equal to a second preset speed. The heating method in the post-heating stage includes: dividing the preheating temperature range into 4 to 6 post-heating levels according to the temperature gradient based on the preset preheating temperature lower limit value and the preheating temperature upper limit value range; The heating mode of each post-heating level is divided into 4 to 6 heating steps, and a grid heating pulse width modulation signal corresponding to each heating step is set according to each heating step; wherein the grid heating pulse width modulation signal of each heating step includes a heating duration and a pulse width modulation signal output duty cycle corresponding to the heating duration; According to the preheating temperature obtained by analysis, the afterheating level of the preheating temperature is determined, and the air intake grille is heated according to the grille heating pulse width modulation signal of each heating step under the corresponding afterheating level.

5. A diesel engine air intake grille heating control system, used to implement the diesel engine air intake grille heating control method according to any one of claims 1 to 4, characterized in that: include: a data processing module, configured to collect the intake air temperature and coolant temperature of the diesel engine when the controller is started, and calculate the preheating temperature based on the intake air temperature and the coolant temperature; a stage division module, configured to divide the diesel engine air intake grille heating process into a preparation stage, a preheating stage, and a starting stage, starting from the start of the diesel engine controller and based on the controller operation time and the diesel engine speed; wherein the preparation stage is a period from the start of the diesel engine controller to a preset delay time, the preheating stage is a period from the preset delay time to the time when the diesel engine speed is less than a first preset speed, and the starting stage is a period from the time when the diesel engine speed is greater than or equal to the first preset speed and less than a second preset speed; A heating control module uses a pulse width modulator to control grille heating and terminates grille heating when all heating stages are completed, the coolant temperature is higher than a third temperature threshold, or the diesel engine is in a steady state; wherein the heating control module includes: a preparation stage control unit, configured to, after the diesel engine air intake grille heating state is in the preparation stage, use a pulse width modulator to control the grille heating pulse width modulation signal output duty cycle to be 0%; a preheating stage control unit, configured to control grille heating according to a preset preheating time threshold after the diesel engine air intake grille enters the preheating stage, wherein: if the preheating stage duration is less than or equal to the preset preheating time threshold, the grille heating pulse width modulation signal output duty cycle is 100%; if the preheating stage duration exceeds the preset preheating time threshold, then after the preheating time threshold, the grille heating pulse width modulation signal output duty cycle is 0%; The starting phase control unit is used to, after the diesel engine air intake grille enters the starting phase in the heating state, if the preheating temperature is less than the first temperature threshold and the starting phase is maintained within 10 seconds, the grille heating pulse width modulation signal output duty cycle is 100%, otherwise the grille heating pulse width modulation signal output duty cycle is 0%.

6. The diesel engine air intake grille heating control system according to claim 5, characterized in that: In the heating control module, the preheating temperature is determined according to T s =k·T co +(1-k)T ch The analysis results show that T s is the preheating temperature, k is the temperature weight coefficient, the value range of k is 0~1, T co is the coolant temperature, T ch is the intake air temperature.

7. The diesel engine air intake grille heating control system according to claim 6, characterized in that: In the heating control module, the preset preheating time threshold is based on The analysis results show that t p is the warm-up time threshold, T s is the preheating temperature, and w is the heating rate of the air intake grille when the duty cycle of the grille heating pulse width modulation signal output is 100%.

8. The diesel engine air intake grille heating control system according to claim 5, characterized in that: The heating control module also includes a post-heating stage control unit, which is used to divide the preheating temperature range into 4 to 6 post-heating levels according to the temperature gradient according to the preset preheating temperature lower limit value and the preheating temperature upper limit value range within the time period when the diesel engine speed is greater than or equal to the second preset speed; and divide the heating mode of each post-heating level into 4 to 6 heating steps, and set the grille heating pulse width modulation signal corresponding to each heating step according to each heating step; wherein the grille heating pulse width modulation signal of each heating step includes a heating time and a pulse width modulation signal output duty cycle under the corresponding heating time; based on the preheating temperature obtained by analysis, determine the post-heating level at which the preheating temperature is located, and heat the air intake grille according to the grille heating pulse width modulation signal of each heating step under the corresponding post-heating level.

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