A method for self-positioning control of a VGT valve reference position

Abstract

The application discloses a VGT valve reference position self-positioning control method, which comprises the following steps: when a set pretreatment condition is met, a valve body is controlled to perform pretreatment; the valve body is controlled to perform minimum position self-positioning to determine a self-positioning minimum reference value; the valve body is controlled to perform maximum position self-positioning to determine a self-positioning maximum reference value; after the minimum position self-positioning and the maximum position self-positioning are successful, the minimum position self-positioning reference value and the maximum position self-positioning reference value are updated. The method improves the valve body control precision by updating the position reference value of the valve body, and further improves the control precision of the supercharging pressure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engines, in particular to a VGT valve reference position self-positioning control method. BACKGROUND

[0002] A variable cross-section supercharger (VGT) is used to control the guide vanes of the cross section, and the adjustable guide vanes are controlled by an engine control unit to enter the airflow of the turbocharger. Studies have shown that the VGT system can improve the supercharging pressure and the response speed of the supercharger, achieve a lower speed corresponding to the maximum torque, have more working conditions of the supercharger in the engine MAP, and improve the thermal efficiency of the engine.

[0003] The prior art CN113006931A discloses a variable cross-section supercharger non-intelligent electronic actuator control method and device: when the ECU is first operated, the feedback voltage a' is obtained by driving the crank to reach the full opening mechanical stop position. The difference between the actual value a' of the feedback voltage and the theoretical value a is calculated, and the initial assignment in the ECU is modified using the difference, to obtain the feedback voltage limit value of the effective running interval and the buffer position of the vane. After the machine is operated for a long time, the mechanical position may be offset due to wear, and the self-learning function is executed under specific conditions when the engine is started or stopped, the feedback voltage is re-acquired by driving the crank to reach the full opening mechanical stop position, the initial assignment in the ECU module is modified again by calculating the difference from the theoretical value a, to ensure the accuracy of the actuator running position.

[0004] The defects of the prior art are that the minimum effective working gap between the guide vanes of the VGT and the valve working interval that can be normally used by the VGT are not considered, the actual minimum and maximum positions are completely used, the stable state of the valve body at the stop position is not considered, and the reference inaccuracy and the valve body unable to work caused by the jamming of the valve body are not considered. SUMMARY

[0005] The purpose of the present application is to provide a VGT valve reference position self-positioning control method to improve the control accuracy of the VGT valve and further improve the control accuracy of the supercharging pressure.

[0006] To solve the above technical problems, the present application provides a technical scheme: a VGT valve reference position self-positioning control method, comprising:

[0007] When the set pretreatment condition is met, the valve body is controlled to perform pretreatment;

[0008] The valve body is controlled to perform minimum position self-positioning to determine a self-positioning minimum reference value;

[0009] The valve body is controlled to perform maximum position self-positioning to determine a self-positioning maximum reference value;

[0010] After the minimum position self-positioning and the maximum position self-positioning are successful, the minimum position self-positioning reference value and the maximum position self-positioning reference value are updated; when the valve body request opening degree is received, the valve body actual opening degree is determined according to the valve body actual position, the minimum position self-positioning reference value and the maximum position self-positioning reference value, and then the valve body is controlled according to the valve body actual opening degree and the valve body request opening degree.

[0011] According to the above scheme, the pretreatment condition is that:

[0012] 1) the driving cycle is ended;

[0013] 2) the engine is stopped;

[0014] 3) the key signal is in the power-off lock state;

[0015] When the above conditions are met at the same time for a certain time, the pretreatment condition is met.

[0016] According to the above scheme, the method for controlling the valve body to perform pretreatment comprises:

[0017] forward pretreatment: controlling the valve body to move to a valve opening degree pretreatment maximum target position and staying at the valve opening degree pretreatment maximum target position after reaching the valve opening degree pretreatment maximum target position, and exiting the forward pretreatment when the valve body reaches the valve opening degree pretreatment maximum target position or the operation time of this step exceeds a preset time;

[0018] reverse pretreatment: controlling the valve body to move to a valve opening degree pretreatment minimum target position and staying at the valve opening degree pretreatment minimum target position after reaching the valve opening degree pretreatment minimum target position, and exiting the reverse pretreatment when the valve body reaches the opening degree pretreatment minimum target position or the operation time of this step exceeds a preset time;

[0019] repeating the forward pretreatment and the reverse pretreatment for a preset number of times;

[0020] The valve opening degree pretreatment maximum target position and the valve opening degree pretreatment minimum target position are obtained through calibration.

[0021] According to the above scheme, the method for controlling the valve body to perform minimum position self-positioning comprises:

[0022] taking a preset initial position as a target position of the valve body, if the valve body successfully reaches the target position and remains for a certain time, then entering the next target position; the target position is gradually reduced by a fixed step;

[0023] When a certain sampling period meets a set first valve body mechanical stop point judgment condition, a set first count value starts to accumulate with the number of elapsed sampling periods, and when a certain sampling period does not meet the first valve body mechanical stop point judgment condition, the first count value is cleared.

[0024] When the set first count value reaches the set maximum count number, a self-positioning minimum reference value is determined according to the valve body position of the previous several sampling periods of the current sampling period, at which time the minimum position self-positioning ends and the maximum position self-positioning is entered;

[0025] When the minimum position self-positioning time exceeds the set maximum learning time limit, the set maximum / minimum position self-positioning failure number is increased by one, the set minimum position self-positioning failure flag is set to 1, if the maximum / minimum position self-positioning failure number is less than the set maximum self-learning number at this time, the minimum position self-positioning is re-performed, otherwise the minimum position self-positioning is exited.

[0026] According to the above scheme, the first valve body mechanical stop point judgment condition is:

[0027] 1) the valve body position is less than the preset valve body minimum position limit;

[0028] 2) the valve body position change rate is less than the preset valve body position change rate stability limit;

[0029] 3) the valve body control final request duty cycle is less than or equal to the preset valve body minimum position stability duty cycle limit;

[0030] When the above conditions are met at the same time, the first valve body mechanical stop point judgment condition is met.

[0031] According to the above scheme, the method for controlling the valve body to perform maximum position self-positioning includes:

[0032] The preset initial position is taken as the target position of the valve body, if the valve body successfully reaches the target position and remains for a certain time, the next target position is entered; the target position is gradually increased by a fixed step;

[0033] When a certain sampling period meets the set second valve body mechanical stop point judgment condition, the set second count value starts to accumulate with the number of elapsed sampling periods, when a certain sampling period does not meet the second valve body mechanical stop point judgment condition, the second count value is cleared;

[0034] When the set second count value reaches the set maximum count number, a self-positioning maximum reference value is determined according to the valve body position of the previous several sampling periods of the current sampling period, at which time the maximum position self-positioning ends and the set self-positioning completion flag is set to 1;

[0035] When the maximum position self-positioning time exceeds the set maximum learning time limit, the set maximum / minimum position self-positioning failure number is increased by one, the set maximum position self-positioning failure flag is set to 1, if the maximum / minimum position self-positioning failure number is less than the set maximum self-learning number at this time, the maximum position self-positioning is re-performed, otherwise the maximum position self-positioning is exited.

[0036] According to the above scheme, the second valve body mechanical stop point judgment condition is:

[0037] 1) The valve body position is greater than the preset valve body maximum position limit value;

[0038] 2) The valve body position change rate is less than the preset valve body position change rate stability limit value;

[0039] 3) The valve body control final request duty cycle is greater than or equal to the preset valve body maximum position stability duty cycle limit value;

[0040] When the above conditions are met at the same time, the second valve body mechanical stop point judgment condition is met.

[0041] According to the above scheme, the method for updating the minimum position self-positioning reference value comprises:

[0042] When the self-positioning minimum reference value of the current driving cycle is less than the preset minimum reference value, the minimum positioning reference output value of the current driving cycle is equal to the minimum reference value;

[0043] When the self-positioning minimum reference value of the current driving cycle is not less than the preset minimum reference value, the minimum positioning reference output value of the current driving cycle is equal to the self-positioning minimum reference value;

[0044] The minimum positioning reference output value of the current driving cycle is weighted with the currently stored minimum self-positioning reference value to obtain an updated minimum self-positioning reference value and store it;

[0045] The method for updating the maximum position self-positioning reference value comprises:

[0046] When the self-positioning maximum reference value of the current driving cycle is less than the preset maximum reference value, the maximum positioning reference output value of the current driving cycle is equal to the self-positioning maximum reference value of the current driving cycle;

[0047] When the self-positioning maximum reference value of the current driving cycle is not less than the preset maximum reference value, the maximum positioning reference output value of the current driving cycle is equal to the preset maximum reference value;

[0048] The maximum positioning reference output value of the current driving cycle is weighted with the currently stored maximum self-positioning reference value to obtain an updated maximum self-positioning reference value and store it.

[0049] According to the above scheme, when the maximum / minimum position self-positioning failure number is greater than the set maximum / minimum position self-positioning failure number limit value, and the maximum position self-positioning failure flag bit is 1, the valve body is controlled to perform opening direction deep cleaning;

[0050] When the maximum / minimum position self-positioning failure number is greater than the set maximum / minimum position self-positioning failure number limit value, and the maximum position self-positioning failure flag bit is 1, the valve body is controlled to perform deep cleaning in the closing direction.

[0051] According to the above scheme, the method for controlling the valve body to perform deep cleaning in the opening direction comprises:

[0052] According to the valve body maximum position limit value and the preset first deep cleaning position offset, a first closing target position and a first opening target position are determined.

[0053] A first closing cumulative time is started to be accumulated, and the valve body is controlled to move to the closing position direction at a certain output duty ratio.

[0054] When the actual position of the valve body is less than the first closing target position, and the accumulated first closing cumulative time is greater than the set first closing maximum time, subsequent steps are performed.

[0055] A first opening cumulative time is started to be accumulated, and the valve body is controlled to move to the opening position direction at a certain output duty ratio.

[0056] When the actual position of the valve body is greater than the first opening target position, and the first opening cumulative time is less than the set first opening maximum time, it is determined that the deep cleaning in the opening direction is successful; otherwise, it is determined that the deep cleaning in the opening direction fails, and the set opening direction deep cleaning failure number is incremented by one.

[0057] When the opening direction deep cleaning failure number is less than the set maximum opening direction deep cleaning failure number, the deep cleaning in the opening direction is re-performed; otherwise, a deep cleaning failure information is sent out.

[0058] The method for controlling the valve body to perform deep cleaning in the closing direction comprises:

[0059] According to the valve body minimum position limit value and the preset second deep cleaning position offset, a second closing target position and a second opening target position are determined.

[0060] A second opening cumulative time is started to be accumulated, and the valve body is controlled to move to the opening position direction at a certain output duty ratio.

[0061] When the actual position of the valve body is greater than the second opening target position, and the second opening cumulative time is greater than the set second opening maximum time, subsequent steps are performed.

[0062] A second closing cumulative time is started to be accumulated, and the valve body is controlled to move to the closing position direction at a certain output duty ratio.

[0063] When the actual position of the valve body is less than the second closing target position, and the second closing cumulative time is less than the set second closing maximum time, it is determined that the opening direction deep cleaning is successful; otherwise, it is determined that the opening direction deep cleaning fails, and the set closing direction deep cleaning failure number is increased by one;

[0064] When the closing direction deep cleaning failure number is less than the set closing direction deep cleaning maximum failure number, the closing direction deep cleaning is re-performed; otherwise, the deep cleaning failure information is sent out.

[0065] The beneficial effects of the present application are: by self-positioning the valve body, updating the minimum / maximum position self-positioning reference value, and further compensating for the reference deviation caused by engine production differences, wear and aging, etc., while avoiding the VGT valve body entering the abnormal running interval.

[0066] Further, when the self-positioning fails, the valve body is deep cleaned to solve the problems of VGT valve sticking or inaccurate reference position and inability to work caused by emission particles or other reasons. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 is a VGT valve reference position self-positioning control method flow chart of the first embodiment of the present application. DETAILED DESCRIPTION

[0068] To make the purposes, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without any creative effort belong to the scope of protection of the present disclosure.

[0069] The present embodiment discloses a VGT valve reference position self-positioning control method, comprising the following steps:

[0070] S1, when the set pre-treatment condition is met, the valve body is controlled to be pre-treated

[0071] When a driving cycle ends, the engine is stopped, and the key signal is in the power-off lock state, the pre-treatment condition is met. To prevent false triggering, a power-off delay condition is set. When the above condition is met for a certain time (5s is set in the present example), the delay condition is reached, and the pre-treatment is triggered.

[0072] The pre-treatment process includes:

[0073] S1.1, set the valve opening degree pre-treatment maximum target position and the valve opening degree pre-treatment minimum target position of the valve through calibration.

[0074] S1.2, control the valve body to perform forward pretreatment; the forward pretreatment is: control the valve body to move to the valve opening pretreatment maximum target position, and stay after reaching the valve opening pretreatment maximum target position, when the valve body reaches the valve opening pretreatment maximum target position or the operation time of this step exceeds the preset time, exit the forward pretreatment.

[0075] S1.3, control the valve body to perform reverse pretreatment; the reverse pretreatment is: control the valve body to move to the valve opening pretreatment minimum target position, and stay after reaching the valve opening pretreatment minimum target position, when the valve body reaches the opening pretreatment minimum target position or the operation time of this step exceeds the preset time, exit the reverse pretreatment.

[0076] S1.4, repeat the forward pretreatment and the reverse pretreatment for a preset number of times to remove foreign matter from the valve body.

[0077] S2, control the valve body to perform minimum position self-positioning to determine a self-positioning minimum reference value

[0078] After the pretreatment is completed, activate the minimum position self-positioning, and simultaneously perform timing, the cumulative time of the minimum position self-positioning is represented as T sum1 , which is initialized as 0, and the minimum position self-positioning failure flag is represented as FailFlag min , which is initialized as 0.

[0079] S2.1, minimum position self-positioning process:

[0080] Take a preset initial position as the target position of the valve body, if the valve body successfully reaches the target position and maintains for a certain time, then enter the next target position; the target position is gradually reduced by a fixed step; all target positions need to be maintained for a certain time.

[0081] S2.2, minimum position self-positioning judgment:

[0082] Set the first valve body mechanical stop point judgment condition as:

[0083] a) the valve body position is less than a preset valve body minimum position limit value; specifically as follows:

[0084] Pos act < Pos lrn_min

[0085] Wherein Pos act is the valve body position, and Pos lrn_min is the preset valve body minimum position limit value, which is taken as 20% in this example

[0086] b) the valve body position change rate is less than a preset valve body position change rate stability limit value; specifically as follows:

[0087] Posact_dev <Pos lrn_min_dev

[0088] Pos act_dev = | (Pos act - Pos act(z) ) / T samp )|

[0089] Where Pos act(z) is the valve position value of last sampling period, T samp is the sampling period, which is set to 10ms in this example, Pos act_dev is the valve position rate of change, Pos lrn_min_dev is the preset valve position rate of change stability limit, which is set to 10% in this example.

[0090] c) At the same time, the valve control request duty cycle is less than or equal to the preset minimum valve position stability duty cycle limit, specifically as follows:

[0091] Pct ControllerOutput< = Pct Lrn_Min_FinalDC

[0092] Where Pct ControllerOutput is the valve control request duty cycle, Pct Lrn_Min_FinalDC is the preset minimum valve position stability duty cycle limit, which is set to -10% in this example.

[0093] If the above conditions are met at the same time, it is considered that the first valve mechanical stop point judgment condition is met; it indicates that the valve has reached the mechanical stop point at this time.

[0094] S2.3, self-positioning minimum reference value calculation:

[0095] When a sampling period meets the first valve mechanical stop point judgment condition, the first count value Count min is set to start accumulating with the number of sampling periods passed, and the maximum count number Count min_limit is set (10 in this example), and when the first count value reaches the maximum count number, the self-positioning minimum reference value Pos Mincur is calculated.

[0096]

[0097] Where Pos act_i , i = 1 ~ 10 represents the valve position of the first 10 sampling periods of this sampling period;

[0098] When the first count reaches the maximum count number Count min_limit , it indicates that the minimum position self-positioning is completed. Enter the maximum position self-positioning.

[0099] The first count value Count is set min If any of the first valve mechanical end point judgment conditions is not met during the accumulation process, Count min is reset to 0, the first valve mechanical end point judgment is performed again, the count is activated again if the judgment condition is met, and the process is repeated.

[0100] S2.4, minimum position self-positioning fails:

[0101] During the above process, when the cumulative time T sum1 of minimum position self-positioning exceeds the set maximum learning time limit T max (the maximum learning time limit T max in this example is set to 2s), it indicates that the minimum position self-positioning fails, and the following operations are performed:

[0102] Cnt fail = Cnt fail+ 1;

[0103] FailFlag min = 1;

[0104] Cnt fai is the number of maximum / minimum position self-positioning failures;

[0105] Cnt max is the maximum self-learning number, which is set to 3 in this example.

[0106] When Cnt fail <Cnt max , the minimum position self-positioning is restarted.

[0107] When Cnt fail > = Cnt max , the self-learning is exited and the subsequent deep cleaning is performed.

[0108] S3, control valve to perform maximum position self-positioning to determine the maximum reference value of self-positioning

[0109] Maximum position self-positioning is activated, and timing is performed simultaneously. The cumulative time of maximum position self-positioning is represented as T sum2 , which is initialized to 0. The maximum position self-positioning failure flag is represented as FailFlag max , which is initialized to 0.

[0110] S3.1, maximum position self-positioning process:

[0111] The preset initial position is used as the target position of the valve. If the valve successfully reaches the target position and remains for a certain period of time, the next target position is entered. The target position is gradually increased in fixed steps. All target openings need to be maintained for a certain period of time.

[0112] S3.2, Maximum position self-positioning judgment:

[0113] The second valve body mechanical stop point judgment condition is set as:

[0114] a) The valve body position is greater than the preset valve body maximum position limit value, specifically as follows:

[0115] Pos act >Pos lrn_max

[0116] Wherein Pos act is the valve body position, and Pos lrn_max is the preset valve body maximum position limit value, which is 90% in the present example.

[0117] b) The valve body position change rate is less than the preset valve body position change rate stability limit value; specifically as follows:

[0118] Pos act_dev <Pos lrn_min_dev

[0119] c) At the same time, the valve body control request duty cycle is greater than or equal to the preset valve body maximum position stability duty cycle limit value, specifically as follows:

[0120] Pct ControllerOutput> =Pct Lrn_Max_FinalDC

[0121] Wherein, Pct Lrn_Min_FinalDC is the preset valve body maximum position stability duty cycle limit value, which is 80% in the present example.

[0122] At the same time, the above conditions are met, and it is considered that the second valve body mechanical stop point judgment condition is met; it indicates that the valve body has reached the mechanical stop point at this time.

[0123] S3.3, Self-positioning maximum reference value calculation:

[0124] When a certain sampling period meets the second valve body mechanical stop point judgment condition, the second count value Count max is set to start accumulation, and the maximum count number Count max_limit is set, which is 10 in the present example. When the second count value reaches the maximum count number, the self-positioning maximum reference value Pos Maxcur is calculated.

[0125]

[0126] Wherein Pos act_i , i = 1 ~ 10 represents the valve body position of the first 10 sampling periods of the present sampling period.

[0127] When the first count reaches the maximum count number Countmax_limit At the same time, it also indicates that the maximum position self-positioning is completed. End the self-positioning and set the self-positioning completion flag Flag finish = 1.

[0128] When the set second count value Count max In the accumulation process, if any of the second valve body mechanical stop point judgment conditions is not met, Count max is reset to 0, then the second valve body mechanical stop point judgment is performed again, and the count is activated again when the judgment condition is met, and the process is repeated.

[0129] S3.4, maximum position self-positioning fails:

[0130] In the above process, when the accumulation time T sum2 of the maximum position self-positioning exceeds the set maximum learning time limit T max (the maximum learning time limit T max of the present example is set to 2s), it indicates that the maximum position self-positioning fails, and the following operations are performed:

[0131] Cnt fail = Cnt fail+ 1;

[0132] FailFlag max = 1;

[0133] When Cnt fail< Cnt max , the minimum position self-positioning is restarted.

[0134] When Cnt fail> = Cnt max , the self-positioning is exited and the subsequent deep cleaning is performed.

[0135] S4, update the minimum position self-positioning reference value and the maximum position self-positioning reference value

[0136] S4.1 update the minimum self-positioning reference value

[0137] When the self-positioning completion flag Flag finish = 1, the following operations are performed:

[0138] define Pos Minout as the minimum positioning reference output value of this time,

[0139] When the self-positioning minimum reference value Pos Mincur of this driving cycle is less than the preset minimum reference value Pos Minref , make the minimum positioning reference output value Pos Minout of this driving cycle equal to the minimum reference value Pos Minref ;

[0140] Pos Minout = Pos Minref

[0141] When the self-positioning minimum reference value Pos Mincur of the current driving cycle is not less than the preset minimum reference value Pos Minref , the minimum positioning reference output value Pos Minout of the current driving cycle is equal to the self-positioning minimum reference value Pos Mincur .

[0142] Pos Minout = Pos Mincur

[0143] The minimum positioning reference output value Pos Minout of the current driving cycle is weighted with the currently stored minimum self-positioning reference value Pos Minfinal(ne) to obtain an updated minimum self-positioning reference value Pos Minfinal , which ensures that the single reference position value is not sudden, and the specific calculation is as follows:

[0144] Pos Minfinal = K * Pos Minout + Pos Minfinal(ne) *(1-K)

[0145] The value of K in the present example is 0.2.

[0146] The minimum self-positioning reference value Pos Minfinal is stored (the minimum self-positioning reference value Pos Minfinal is not lost after power-off and is used as the minimum self-positioning reference value for the next driving cycle).

[0147] S4.2, updating the maximum self-positioning reference value

[0148] When the self-positioning maximum reference value Pos Maxcur of the current driving cycle is less than the preset maximum reference value Pos Maxref , the maximum positioning reference output value Pos Maxout of the current driving cycle is equal to the self-positioning maximum reference value Pos Maxcur of the current driving cycle.

[0149] Pos Maxout = Pos Maxcur

[0150] When the self-positioning maximum reference value Pos Maxcur of the current driving cycle is not less than the preset maximum reference value Pos Maxref , the maximum positioning reference output value Pos MaxoutEqual to the preset maximum reference value Pos Maxref ;

[0151] Pos_Max out = Pos_Max ref

[0152] The maximum positioning reference output value Pos Maxout of this driving cycle is weighted with the currently stored maximum self-positioning reference value Pos Maxfinal(ne) to obtain an updated maximum self-positioning reference value Pos Maxfinal , which ensures that the single reference position value will not be abrupt, and the specific calculation is as follows:

[0153] Pos Maxfinal = K * Pos Maxout + Pos Maxfinal(ne) *(1-K)

[0154] The value of K in this example is 0.2.

[0155] The maximum self-positioning reference value Pos Maxfinal is stored (the maximum self-positioning reference value Pos Maxfinal is stored and will not be lost after power-off, and will be used as the maximum self-positioning reference value for the next driving cycle).

[0156] After the above steps, the minimum self-positioning reference value Pos Minfinal and the maximum self-positioning reference value Pos Maxfinal are obtained, and the valve control effect is as follows: when receiving the valve request opening, the actual valve opening is determined according to the actual valve position, the minimum position self-positioning reference value, and the maximum position self-positioning reference value, and then the valve is controlled (for example, closed loop control) according to the actual valve opening and the valve request opening, and the specific calculation is as follows:

[0157] Actual opening = (Pos act - Pos Minfinal ) / (Pos Maxfinal - Pos Minfinal )

[0158] S5, Valve deep cleaning

[0159] S5.1 Start direction deep cleaning

[0160] S5.1.1, Activation condition

[0161] The following conditions are met simultaneously to activate the opening direction cleaning:

[0162] Condition 1: Cnt fail> = Cnt max ;

[0163] Condition 2: FailFlag is a flag indicating that self-positioning fails max = 1;

[0164] S5.1.2, target position setting

[0165] Set the first closing target position Pos1 of the valve body CloseTarget , the first opening target position Pos1 OpenTarget ,

[0166] Set the first deep cleaning position offset Pos1 MinOffset , which is set to 5% in this example, Pos lrn_min is the maximum position limit of the valve body in the previous step.

[0167] Pos1 CloseTarget = Pos lrn_max - Pos1 MinOffset ;

[0168] Pos1 OpenTarget = Pos lrn_max + Pos1 MinOffset ;

[0169] S5.1.3, closing direction control

[0170] First activate the closing direction control and set the first closing cumulative time Time1 Close , initialized to 0, which is continuously accumulated after activation.

[0171] Control the valve body to move in the opposite direction of the stuck direction, specifically, perform open-loop control on the valve body, control the valve motor output opening duty ratio (in this example, -50%), and move in the closing position direction,

[0172] When any of the following conditions are met, it indicates that the valve body has moved away from the stuck position,

[0173] Pos act < Pos1 CloseTarge

[0174] Time1 Close > Time1 CloseMax

[0175] Time1 CloseMax is the first closing maximum time, which is set to 0.5s in this example.

[0176] S5.1.4, opening direction control

[0177] Perform open-loop control on the valve body and set the first opening cumulative time Time1 Open , initialized to 0, which is continuously accumulated after activation.

[0178] The control valve motor output open duty cycle (50% in this example) is turned on to move in the open direction, impacting and crushing in the open direction.

[0179] When the following conditions are met, it indicates that the actual position of the valve body reaches the first opening target position, and the deep cleaning is successful:

[0180] Pos act > Pos1 OpenTarge

[0181] Time1 Open < Time1 OpenMax

[0182] First opening maximum time Time1 OpenMax = 2s.

[0183] When the following conditions are met, it indicates that the actual position of the valve body does not reach the first opening target position, and the deep cleaning fails:

[0184] Pos act <= Pos1 OpenTarge

[0185] Time1 open >= Time1 OpenMax

[0186] S5.1.5 Result Judgment

[0187] Set the number of opening direction deep cleaning failures Cnt OpenFail , the maximum number of opening direction deep cleaning failures Cnt OpenFailMax = 3, when the opening direction deep cleaning fails this time, the number of opening direction deep cleaning failures Cnt Openfail is incremented by one. Cnt OpenFail = Cnt OpenFail + 1

[0188] When the number of opening direction deep cleaning failures Cnt OpenFail< Cnt OpenFailMax , the opening direction deep cleaning is performed again.

[0189] When the number of opening direction deep cleaning failures Cnt OpenFail >= Cnt OpenFailMax , it indicates that the deep cleaning has completely failed, and sends a fault flag to the diagnostic module for code reporting.

[0190] S5.2 Deep Cleaning in Closing Direction

[0191] S5.2.1 Activation Condition

[0192] The following conditions are met simultaneously, and the closing direction cleaning is activated

[0193] Condition 1: Cnt fail> =Cnt max ;

[0194] Condition 2: FailFlag for determining self-location failure min =1;

[0195] S5.2.2 Target Location Setting

[0196] Set the valve body to the second closed target position Pos2 CloseTarget， Second target location Pos2 OpenTarget Set the deep cleaning position offset Pos2 MinOffset In this example, the value is set to 5%, Pos. lrn min This is the minimum position limit of the valve body preset in the third step.

[0197] Pos2 CloseTarget =Pos lrn_min -Pos2 MinOffset ;

[0198] Pos2 OpenTarget =Pos lrn_min +Pos2 MinOffset ;

[0199] S5.2.3 Activate steering control

[0200] First, activate the opening direction control and set the second opening cumulative time, Time2. open Initialized to 0, it continuously accumulates after activation. The control valve body moves in the opposite direction to the stuck position; specifically, it performs open-loop control of the valve body, controlling the valve motor output opening duty cycle (50% in this example) to move it towards the open position.

[0201] When any of the following conditions are met, it indicates that the valve body has moved away from the stuck position, and the opening and closing control is activated:

[0202] Pos act >Pos2 OpenTarge

[0203] Time2 open Time2 OpenMax

[0204] Time2 OpenMax The second maximum activation time is set to 0.5s in this example.

[0205] S5.2.4, Turn off steering control

[0206] Set the second closing cumulative time Time2close , initialized to 0, continuously accumulated after activation.

[0207] The valve body is open-loop controlled, and the control valve motor output opening duty ratio (this example is -50%) is controlled to move in the closing direction, impacting and crushing in the closing direction.

[0208] When the following conditions are met at the same time, it means that the actual position of the valve body reaches the second closing target position, and the deep cleaning is successful:

[0209] Pos act < Pos2 CloseTarge

[0210] Time2 close < Time2 CloseMax

[0211] Time2 CloseMax is the second opening maximum time, this example is set to 2s,

[0212] When the following conditions are met at the same time, it means that the actual position of the valve body does not reach the second closing target position, and the deep cleaning fails:

[0213] Pos act > = Pos2 CloseTarge

[0214] Time2 close > = Time2 closeMax

[0215] S5.2.5, result judgment

[0216] Set the number of deep cleaning failures in the closing direction Cnt CloseFail , the maximum number of deep cleaning failures Cnt CloseFailMax = 3, when the current deep cleaning in the closing direction fails, the number of deep cleaning failures in the closing direction Cnt Closefail is incremented by one.

[0217] Cnt CloseFail = Cnt CloseFail + 1

[0218] When the number of deep cleaning failures in the closing direction Cnt CloseFail < Cnt ClosefailMax , the deep cleaning in the closing direction is re-performed.

[0219] When the number of deep cleaning failures in the closing direction Cnt CloseFail > = Cnt ClosefailMax , it means that the deep cleaning has completely failed, and sends a fault flag to the diagnostic module for code reporting.

[0220] Example two:

[0221] The embodiment discloses a computer device for implementing the method of embodiment one. The computer device can be a smartphone, a tablet computer, a notebook computer, a desktop computer, a rack server, a blade server, a tower server, or a cabinet server (including a single server or a server cluster composed of multiple servers) that can execute programs. The computer device of the embodiment at least includes, but is not limited to, a memory and a processor that can be connected to each other in communication through a system bus. It should be noted that only the computer device with components is shown, but it should be understood that all the shown components are not required to be implemented, and more or fewer components can be alternatively implemented.

[0222] In the embodiment, the memory (i.e., a readable storage medium) includes a flash memory, a hard disk, a multimedia card, a card-type memory (for example, an SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), and can also be an external storage device of the computer device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the computer device. Of course, the memory can also include both an internal storage unit and an external storage device of the computer device. In the embodiment, the memory is usually used to store an operating system and various application software installed on the computer device, such as program codes of the VGT valve reference position self-positioning control method in embodiment one, etc. In addition, the memory can also be used to temporarily store various data that have been output or will be output.

[0223] The processor in some embodiments can be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chips. The processor is usually used to control the overall operation of the computer device. In the embodiment, the processor is used to run program codes or process data stored in the memory, such as running the VGT valve reference position self-positioning control method.

[0224] Embodiment three:

[0225] The embodiment provides a computer readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card memory (for example, an SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disk, an optical disk, a server, an App application market, etc., which stores a computer program, and the program is executed by a processor to realize corresponding functions. The computer readable storage medium of the embodiment is used for storing the program code of the VGT valve reference position self-positioning control method, and the program code is executed by the processor to realize the VGT valve reference position self-positioning control method of the embodiment one.

[0226] It should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiment of the application.

[0227] It should be pointed out that, according to the needs of implementation, each step / component described in the present application can be split into more steps / components, or two or more steps / components or part of the operation of the step / component can be combined into a new step / component to realize the purpose of the present application.

[0228] The above only describes the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent flow transformation obtained by using the content of the specification and drawings of the present application, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method of self-positioning control of a VGT valve reference position, characterized by, The method comprises the following steps: controlling the valve body to perform pretreatment when a set pretreatment condition is met; controlling the valve body to perform minimum position self-positioning to determine a self-positioning minimum reference value; controlling the valve body to perform maximum position self-positioning to determine a self-positioning maximum reference value; after the minimum position self-positioning and the maximum position self-positioning are successful, updating the minimum position self-positioning reference value and the maximum position self-positioning reference value; when a valve body requested opening degree is received, determining a valve body actual opening degree according to the valve body actual position, the minimum position self-positioning reference value and the maximum position self-positioning reference value, and then controlling the valve body according to the valve body actual opening degree and the valve body requested opening degree; the method for controlling the valve body to perform minimum position self-positioning comprises the following steps: taking a preset initial position as a target position of the valve body, and if the valve body successfully reaches the target position and remains for a certain time, entering a next target position; the target position is gradually reduced by a fixed step; when a certain sampling period meets a set first valve body mechanical stop point judgment condition, starting to accumulate a set first count value with the number of the sampling periods that have passed, and when a certain sampling period does not meet the first valve body mechanical stop point judgment condition, clearing the first count value; when the set first count value reaches a set maximum count number, determining the self-positioning minimum reference value according to the valve body positions of the previous sampling periods of the current sampling period, and at this time, the minimum position self-positioning is ended and the maximum position self-positioning is entered; when the minimum position self-positioning time exceeds a set maximum learning time limit value, adding one to a set maximum / minimum position self-positioning failure number, setting a set minimum position self-positioning failure flag bit to 1, and if the maximum / minimum position self-positioning failure number is less than a set maximum self-learning number at this time, re-performing the minimum position self-positioning, otherwise, exiting the minimum position self-positioning.

2. The VGT valve reference position self-positioning control method of claim 1, wherein, The pretreatment condition comprises: 1) a driving cycle is ended; 2) an engine is stopped; 3) a key signal is in a power-off and vehicle locking state; the pretreatment condition is met when the above conditions are met at the same time for a certain time.

3. The VGT valve reference position self-locating control method of claim 1, wherein, The method for controlling the valve body to perform pretreatment comprises the following steps: forward pretreatment: controlling the valve body to move to a valve opening degree pretreatment maximum target position, and staying after reaching the valve opening degree pretreatment maximum target position, and when the valve body reaches the valve opening degree pretreatment maximum target position or the operation time of this step exceeds a preset time, exiting the forward pretreatment; reverse pretreatment: controlling the valve body to move to a valve opening degree pretreatment minimum target position, and staying after reaching the valve opening degree pretreatment minimum target position, and when the valve body reaches the opening degree pretreatment minimum target position or the operation time of this step exceeds a preset time, exiting the reverse pretreatment; repeating the forward pretreatment and the reverse pretreatment for a preset number of times; wherein the valve opening degree pretreatment maximum target position and the valve opening degree pretreatment minimum target position are obtained through calibration.

4. The VGT valve reference position self-locating control method of claim 1, wherein, The first valve body mechanical stop point judgment condition comprises: 1) the valve body position is less than a preset valve body minimum position limit value; 2) the valve body position change rate is less than a preset valve body position change rate stability limit value; 3) the valve body control final request duty cycle is less than or equal to a preset valve body minimum position stability duty cycle limit value; the first valve body mechanical stop point judgment condition is met when the above conditions are met at the same time.

5. The VGT valve reference position self-positioning control method of claim 4, wherein, The method for maximum position self-positioning of the control valve body comprises the following steps: a preset initial position is taken as a target position of the valve body, if the valve body successfully reaches the target position and remains for a certain time, the next target position is entered, and the target position is gradually increased by a fixed step; when a certain sampling period meets a set second valve body mechanical stop point judgment condition, a set second count value starts to accumulate with the number of elapsed sampling periods, and when a certain sampling period does not meet the second valve body mechanical stop point judgment condition, the second count value is cleared; when the set second count value reaches a set maximum count number, a maximum reference value of self-positioning is determined according to the valve body positions of the previous sampling periods of the current sampling period, at this time, the maximum position self-positioning is ended, and a self-positioning completion flag is set to 1; when the performance time of the maximum position self-positioning exceeds a set maximum learning time limit, a set maximum / minimum position self-positioning failure number is increased by 1, a set maximum position self-positioning failure flag is set to 1, if the maximum / minimum position self-positioning failure number is less than a set maximum self-learning number at this time, the maximum position self-positioning is re-performed, otherwise, the maximum position self-positioning is exited.

6. The VGT valve reference position self-positioning control method of claim 5, wherein, The second valve body mechanical stop point judgment condition comprises the following conditions: 1) the valve body position is greater than a preset valve body maximum position limit value; 2) the valve body position change rate is less than a preset valve body position change rate stability limit value; 3) the valve body control final request duty cycle is greater than or equal to a preset valve body maximum position stability duty cycle limit value; when the above conditions are met at the same time, the second valve body mechanical stop point judgment condition is met.

7. The VGT valve reference position self-positioning control method of claim 1, wherein, The method for updating the minimum position self-positioning reference value comprises the following steps: when the self-positioning minimum reference value of the current driving cycle is less than a preset minimum reference value, the minimum positioning reference output value of the current driving cycle is equal to the minimum reference value; when the self-positioning minimum reference value of the current driving cycle is not less than the preset minimum reference value, the minimum positioning reference output value of the current driving cycle is equal to the self-positioning minimum reference value; the minimum positioning reference output value of the current driving cycle and the currently stored minimum self-positioning reference value are weighted to obtain an updated minimum self-positioning reference value and store the same. The method for updating the maximum position self-positioning reference value comprises the following steps: when the self-positioning maximum reference value of the current driving cycle is less than a preset maximum reference value, the maximum positioning reference output value of the current driving cycle is equal to the self-positioning maximum reference value of the current driving cycle; when the self-positioning maximum reference value of the current driving cycle is not less than the preset maximum reference value, the maximum positioning reference output value of the current driving cycle is equal to the preset maximum reference value; the maximum positioning reference output value of the current driving cycle and the currently stored maximum self-positioning reference value are weighted to obtain an updated maximum self-positioning reference value and store the same.

8. The VGT valve reference position self-positioning control method of claim 5, wherein, when the maximum / minimum position self-positioning failure number is greater than a set maximum / minimum position self-positioning failure number limit value, and the maximum position self-positioning failure flag is 1, the valve body is controlled to perform opening direction deep cleaning. When the maximum / minimum position self-positioning failure number is greater than the set maximum / minimum position self-positioning failure number limit value, and the maximum position self-positioning failure flag bit is 1, the valve body is controlled to perform deep cleaning in the closing direction.

9. The VGT valve reference position self-positioning control method of claim 8, wherein, The method for controlling the valve body to perform deep cleaning in the opening direction comprises: determining a first closing target position and a first opening target position according to the valve body maximum position limit value and a preset first deep cleaning position offset; starting to accumulate a first closing accumulated time, and controlling the valve body to move to the closing position direction at a certain output duty ratio; when the valve body actual position is less than the first closing target position, and the accumulated first closing accumulated time is greater than a set first closing maximum time, performing the following steps; starting to accumulate a first opening accumulated time, and controlling the valve body to move to the opening position direction at a certain output duty ratio; when the valve body actual position is greater than the first opening target position, and the first opening accumulated time is less than a set first opening maximum time, determining that the opening direction deep cleaning is successful; otherwise, determining that the opening direction deep cleaning fails, and increasing the set opening direction deep cleaning failure number by one; when the opening direction deep cleaning failure number is less than a set opening direction deep cleaning maximum failure number, re-performing the opening direction deep cleaning; otherwise, sending a deep cleaning failure information to the outside; The method for controlling the valve body to perform deep cleaning in the closing direction comprises: determining a second closing target position and a second opening target position according to the valve body minimum position limit value and a preset second deep cleaning position offset; starting to accumulate a second opening accumulated time, and controlling the valve body to move to the opening position direction at a certain output duty ratio; when the valve body actual position is greater than the second opening target position, and the second opening accumulated time is greater than a set second opening maximum time, performing the following steps; starting to accumulate a second closing accumulated time, and controlling the valve body to move to the closing position direction at a certain output duty ratio; when the valve body actual position is less than the second closing target position, and the second closing accumulated time is less than a set second closing maximum time, determining that the opening direction deep cleaning is successful; otherwise, determining that the opening direction deep cleaning fails, and increasing the set closing direction deep cleaning failure number by one; when the closing direction deep cleaning failure number is less than a set closing direction deep cleaning maximum failure number, re-performing the closing direction deep cleaning; otherwise, sending a deep cleaning failure information to the outside.

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