CN115217624B - Diagnosis method, device, vehicle and storage medium for crankcase ventilation pipe drop-off - Google Patents

Abstract

The invention belongs to the technical field of vehicles, and relates to a crankcase ventilation pipeline falling-off diagnosis method, a crankcase ventilation pipeline falling-off diagnosis device, a vehicle and a computer readable storage medium. The method for diagnosing the falling off of the crankcase ventilation pipeline comprises the following steps: acquiring the current working condition of the vehicle; when the current working condition meets the diagnosis condition, acquiring a pressure value in the crankcase ventilation pipe, and correspondingly acquiring a relative pressure amplitude according to the pressure value; performing a relative pressure amplitude process to obtain a relative pressure amplitude maximum value; comparing all relative pressure amplitude maxima within a drive cycle with diagnostic criteria; and diagnosing according to the comparison result, and outputting a diagnosis result. Therefore, the invention can greatly reduce the probability of false alarm of diagnosis, has high robustness, brings guiding significance for the pipeline drop diagnosis of the installation pressure sensor, and reduces the time and human resources of calibration work.

Description

Diagnosis method, device, vehicle and storage medium for crankcase ventilation pipe drop-off

technical field

The invention belongs to the technical field of vehicles, and in particular relates to a method for diagnosing a crankcase ventilation pipeline falling off, a device for diagnosing a crankcase ventilation pipeline falling off, a vehicle and a computer-readable storage medium.

Background technique

When the engine is running, the unburned mixture in the cylinder may escape into the crankcase through the gap between the piston and the cylinder liner. The function of the crankcase ventilation (PCV) system is to re-introduce the unburned mixture into the cylinder for combustion. However, since the pipeline between the PCV valve and the air-filtered intake pipe is connected by clamps at both ends, there is a risk that the clamps will loosen and the pipeline will fall off, causing the unburned mixer to enter the atmosphere and causing evaporative emissions to exceed the standard. Carry out fault diagnosis and develop a fault management mechanism for pipeline shedding. The existing technology usually adopts the energy value method: record the measured pressure p ₁ in the ventilation pipe of the crankcase, convert p ₁ into an energy value and accumulate it; at the same time, according to the current engine The model pressure p ₂ in the crankcase ventilation duct is calculated from the rotational speed and the engine load, and the p ₂ is converted into an energy value and accumulated. To calculate the deviation dppcv between the cumulative values of _p1 and _p2 , the calculation formula of dppcv is as follows: In the formula, enegy(p ₁ ) is the energy value of the measured pressure; enegy(p ₂ ) is the energy value of the model pressure. When the high-load ventilation pipe is disconnected, enegy(p ₁ )≈0, enegy(p ₂ ) remains unchanged, dppcv≈1; when the high-load ventilation pipe is connected normally, enegy(p ₁ )≈enegy(p ₂ ), dppcv≈0.

However, there are two disadvantages in the energy value method: 1. The current diagnosis scheme diagnoses the shedding fault at both ends of the high-load ventilation pipeline at the same time. Since the energy ratio dppcv calculated near the end of the air intake pipe is relatively large (about 0.99), it is close to the PCV The energy ratio calculated by the valve end falling off is small (about 0.8). In order not to miss faults, the fault threshold is set to be less than 0.8, which increases the risk of false faults. 2. The current diagnosis scheme uses the ratio of the "actual pressure" of the crankcase ventilation pipe and the "model pressure" calibrated by the calibrated vehicle to make a judgment. The difference in PCV pipeline hardware has a great influence, and the coverage of "model pressure" on vehicle differences is insufficient. When the absolute value of "measured pressure" is smaller than the absolute value of "model pressure", dppcv will be close to 1, which increases the risk of false alarm failure. How to solve the shortcoming of the current diagnosis scheme that does not have enough coverage of vehicle differences and is easy to report faults by mistake, so as to meet the purpose of diagnosis is an urgent problem to be solved.

For the above problems, those skilled in the art have been seeking solutions.

The foregoing description is provided to provide general background information and does not necessarily constitute prior art.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for diagnosing crankcase ventilation pipe shedding, a device for diagnosing crankcase ventilation pipe shedding, a vehicle, and a computer-readable storage medium, which can distinguish pipes according to "pressure fluctuations in the crankcase ventilation pipe". The state of whether the road is detached for diagnostic purposes. Therefore, compared with the energy value method, the present invention does not need to calibrate the model pressure of the crankcase ventilation system under different engine operating conditions according to the test vehicle, so as to reduce the influence of vehicle differences on the calibration data, and measure the pressure amplitude after pressure processing according to the PCV pressure sensor. Distinguish between faulty and non-faulty states. The probability of false alarm is extremely low and the robustness is high. It brings instructive significance to the diagnosis of pipeline shedding when the pressure sensor is installed, and reduces the time and human resources of calibration work while greatly reducing the false alarm rate.

The present invention solves its technical problem and adopts following technical scheme to realize:

The invention provides a method for diagnosing that the crankcase ventilation pipe falls off, comprising the following steps: obtaining the current working condition of the vehicle; when the current working condition meets the diagnostic conditions, obtaining the pressure value in the crankcase ventilation pipe, and correspondingly obtaining Perform relative pressure amplitude processing to obtain the maximum value of relative pressure amplitude; compare all relative pressure amplitude maximum values within a driving cycle with diagnostic standard values; perform diagnosis according to the comparison result, and output the diagnosis result.

Further, the aforementioned step of obtaining the current working condition of the vehicle includes: obtaining current temperature information, wherein the current temperature information includes ambient temperature, current engine coolant temperature and delay time; obtaining current engine working condition information, the engine working condition information includes Engine intake flow value, change value of engine intake flow, engine speed and supercharging pressure; obtain the current working information of the pressure sensor.

Further, the aforementioned diagnostic conditions include: when the ambient temperature is higher than the preset temperature threshold, and the delay time reaches the first time threshold; or, when the ambient temperature is lower than the preset temperature threshold, the engine coolant temperature reaches the corresponding coolant temperature threshold , and the corresponding delay time reaches the second time threshold; the engine intake air flow value is within the flow threshold range; the engine intake air flow change value is within the change threshold range; the engine speed is within the preset speed range; Threshold; the working information of the pressure sensor meets the normal working conditions.

Further, the aforementioned step of obtaining diagnostic information when the current working condition satisfies the diagnostic condition includes: when the current working condition meets the diagnostic condition, acquiring a plurality of pressure values according to a preset frequency; calculating the pressure of two adjacent pressure values Sample difference; determine whether the pressure sample difference is greater than 0: if yes, assign the new pressure value of the two pressure values to the pressure wave peak value; if not, assign the new pressure value of the two pressure values to the pressure wave trough value; after each value assignment, calculate the difference between the current peak value of the pressure wave and the current pressure trough value to obtain the corresponding relative pressure amplitude, and save the relative pressure amplitude.

Further, the step of executing the relative pressure amplitude processing to obtain the maximum value of the relative pressure amplitude includes: when the current working condition does not meet the diagnosis condition, control the timer to stop counting; when the current working condition meets the diagnosis condition, control the timing The timer starts timing; judge whether the accumulated time counted by the timer reaches the preset duration; if so, obtain all the relative pressure amplitudes within the accumulated time counted by the timer to obtain the maximum value of the relative pressure amplitude, and reset the timer.

Further, in the aforementioned step of comparing all relative pressure amplitude maximum values within one driving cycle with diagnostic standard values, the diagnostic standard values include failure thresholds and repair thresholds: the aforementioned step of comparing with diagnostic standards includes: if there is a When the maximum value of relative pressure amplitude is less than the fault threshold, the count of the fault counter is increased by 1; if there is a maximum value of relative pressure amplitude greater than the repair threshold, the count of the non-fault counter is increased by 1.

Further, the aforementioned step of diagnosing according to the comparison result and outputting the diagnosis result includes: when the sum of the non-fault counter and the fault counter meets the counting threshold, comparing the count values of the non-fault counter and the fault counter; when the value of the fault counter When the value is greater than the non-fault counter, the output will output a fault warning; when the value of the fault counter is less than the non-fault counter, it will output repair fault prompt information or no fault prompt information.

The present invention also provides a crankcase ventilation pipeline drop-off diagnosis device, which is characterized in that it includes a processor and a memory: the processor is used to execute the computer program stored in the memory to realize the crankcase ventilation pipeline drop-off diagnosis as described above Method steps.

The present invention also provides a vehicle, which includes the aforementioned device for diagnosing the disconnection of the crankcase ventilation pipeline.

The present invention also provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned method for diagnosing the disconnection of the crankcase ventilation pipeline are realized.

The invention also provides a method for diagnosing that the crankcase ventilation pipeline falls off, a diagnostic device for the crankcase ventilation pipeline falling off, a vehicle and a computer-readable storage medium. Wherein, the method for diagnosing the disconnection of the crankcase ventilation pipe includes the following steps: obtaining the current working condition of the vehicle; when the current working condition meets the diagnostic conditions, obtaining the pressure value in the crankcase ventilation pipe, and corresponding to the obtained relative pressure amplitude according to the pressure value; Perform relative pressure amplitude processing to obtain the maximum value of relative pressure amplitude; compare all relative pressure amplitude maximum values within a driving cycle with diagnostic standard values; perform diagnosis according to the comparison result, and output the diagnosis result. Therefore, the present invention can distinguish the state of whether the pipeline falls off according to the "pressure fluctuation in the crankcase ventilation pipe", so as to meet the purpose of diagnosis. Compared with the prior art, the false alarm rate is greatly reduced and the robustness is improved. It brings guiding significance to the diagnosis of pipeline shedding when the pressure sensor is installed, greatly reduces the false alarm rate, reduces the time and human resources of calibration work, reduces the user's operation, increases the convenience of the user, and improves the use of the user experience.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments will be described in detail in conjunction with the accompanying drawings.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is a schematic flow chart of a method for diagnosing the crankcase ventilation pipeline falling off according to the first embodiment of the present invention;

Figure 2 is a schematic diagram of the structure of the PCV system;

Fig. 3 a is the drop point diagram of the test result of the amplitude method provided by the first embodiment of the present invention;

Fig. 3b is a 3-sigma statistical chart of the false positive fault risk of the amplitude method provided by the first embodiment of the present invention;

Figure 4a is a drop point diagram of the test results of the energy value method;

Figure 4b is a 3-sigma statistical chart of the false alarm failure risk of the energy value method;

Fig. 5 is the implementation flowchart of the method for diagnosing that the crankcase ventilation pipeline falls off according to the first embodiment of the present invention;

Fig. 6 is a schematic structural diagram of a diagnostic device for disconnection of the crankcase ventilation pipe provided by the second embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

first embodiment

Fig. 1 is a schematic flow chart of the method for diagnosing the crankcase ventilation pipeline falling off according to the first embodiment of the present invention; Fig. 2 is a schematic diagram of the structure of the PCV system; Fig. 3a to Fig. 3b are experiments of the amplitude method provided by the first embodiment of the present invention Result graphs; FIGS. 4a to 4b are graphs of experimental results of the energy value method provided by the first embodiment of the present invention. In order to clearly describe the method for diagnosing the disconnection of the crankcase ventilation pipe provided by the first embodiment of the present invention, please refer to FIGS. 1-5 .

When the engine is running, the unburned mixture in the cylinder may escape into the crankcase through the gap between the piston and the cylinder liner. The function of the crankcase ventilation (PCV) system is to re-introduce the unburned mixture into the cylinder for combustion. The structure diagram of PCV system is shown in Fig. 2. The PCV valve 2 is connected to the intake pipe 7 through the crankcase ventilation pipe 3, which has two crankcase ventilation pipes 3, and the two ends are connected by clamps. In the middle and high load conditions, there is no negative pressure in the intake manifold 4, but at this time there is a negative pressure in the intake pipe 7 after the air filter, and the blow-by gas in the crankcase can be sucked into the intake pipe 7 through the crankcase ventilation pipe 3, Therefore, the ventilation pipe is also called a high-load ventilation pipe. The pressure sensor 6 is installed on the high-load ventilation pipeline through the pressure sensor 5, and can monitor whether the high-load ventilation pipeline falls off through the pressure situation in the pipeline. Therefore, the present invention designs a device for diagnosing, controlling and fault handling of crankcase ventilation pipeline shedding based on pressure fluctuations in the pipeline. A method for diagnosing the disconnection of the crankcase ventilation pipeline based on the measured pressure fluctuation of the pressure sensor is provided, so as to finally realize the OBD function of the crankcase ventilation pipeline.

In one embodiment, the method for diagnosing the detachment of the crankcase ventilation pipeline can be applied to a diagnostic device for the detachment of the crankcase ventilation pipeline. Specifically, the device can be a functional module of a vehicle-mounted terminal. It can be a diagnostic device installed separately in the PCV system, and there are no technical restrictions on the specific settings and application scenarios. Furthermore, the first embodiment of the present invention provides a method for diagnosing the disconnection of the crankcase ventilation pipeline, which includes the following steps:

Step S1: Obtain the current working condition of the vehicle.

In one embodiment, in step S1: the step of obtaining the current working condition of the vehicle includes: obtaining current temperature information, wherein the current temperature information includes ambient temperature, current engine coolant temperature and delay time; obtaining current engine working condition information , the engine working condition information includes the engine intake flow value, the engine intake flow change value, the engine speed and the supercharging pressure; obtain the current working information of the pressure sensor.

In an embodiment, all the information obtained above on the current working condition can be roughly divided into three types of information: current temperature information, engine working condition information and pressure sensor working information. Specifically, for the current temperature information, because the lower the ambient temperature and/or the lower the temperature of the engine coolant, the PCV pressure sensor 6 has the risk of freezing, which affects the accuracy of the obtained pressure value, thereby affecting the accuracy of the diagnosis result. determination. Therefore, it is necessary to determine that the pressure sensor 6 does not have the risk of icing, and correspondingly, it is necessary to obtain the ambient temperature, the engine coolant temperature and the delay time. For engine working conditions, because the distinction between faults and non-faults is more obvious in supercharged and stable conditions, it is necessary to calibrate the engine speed range, engine intake flow range and engine intake air flow range for diagnosis under engine supercharged conditions. Flow gradient interval. Therefore, it is necessary to correspondingly obtain the value of the intake air flow of the engine, the change value of the intake air flow of the engine, the engine speed and the boost pressure. Finally, for the working information of the pressure sensor, it is confirmed that the pressure value collected by the pressure sensor 6 is accurate and valid, so as to ensure the validity of the diagnosis result.

In one embodiment, the aforementioned diagnostic conditions include: when the ambient temperature is higher than the preset temperature threshold, and the delay time reaches the first time threshold; or, when the ambient temperature is lower than the preset temperature threshold, the engine coolant temperature reaches The corresponding coolant temperature threshold, and the corresponding delay time reaches the second time threshold; the engine intake flow value is within the flow threshold range; the engine intake flow change value is within the change threshold range; the engine speed is within the preset speed range; The boost pressure is greater than the boost threshold; the working information of the pressure sensor meets the normal working conditions.

In one embodiment, the current temperature information is to ensure that the pressure sensor 6 will not have the risk of icing, so for the risk of icing, when the ambient temperature is lower than the preset temperature threshold, in this case, the engine needs to The temperature of the coolant reaches a certain coolant temperature threshold, and when the corresponding delay time exceeds a second time threshold, the diagnosis operation is performed again, so as to eliminate the influence of temperature on the diagnosis result. It can be understood that the temperature is a variable value in real life, so there is a certain correspondence between the ambient temperature, the coolant temperature and the delay time. For this, you can refer to Table 1 and Table 2.

Table 1 Relationship between ambient temperature and engine coolant temperature

Ambient temperature (℃) -30 -9.8 -6.8 0 5.3 9.8 Coolant temperature (℃) 81.8 80.3 69.8 69.8 69.8 50.3

Table 2 The relationship between ambient temperature and delay time

Ambient temperature (℃) -30 -9.8 -6.8 0 5.3 9.8 Delay time (s) 6000 4500 1500 200 900 300

At the same time, it can be seen from the table that the highest ambient temperature in the table is 9.8°C, which means that in this embodiment, the preferred choice for the preset temperature threshold is 9.8°C, that is, when the ambient temperature is higher than 9.8°C , it is considered that there is no risk of pressure sensor 6 icing, so there is no need to consider the temperature of the coolant, and the diagnosis can be started only when the delay time meets the preferred corresponding 300s in the table. When the ambient temperature is lower than 9.8°C, it is necessary to consider the influence of the coolant temperature, and also consider whether the corresponding delay time is satisfied. For example, when the ambient temperature is near 0°C, the engine coolant temperature needs to be delayed for 1200s after reaching 69.8°C. In order to enter the diagnosis, thereby reducing the impact of icing on the diagnosis. Among them, although it is written in the table that the ambient temperature can be lower than minus 30°C, this is for extreme cases. Preferably, the minimum ambient temperature is not lower than minus 10°C.

In one embodiment, for the embodiment of acquiring the engine operating condition information, specifically, the engine operating condition information includes the engine intake flow value, the engine intake flow change value, the engine speed and the supercharging pressure. As mentioned above, because the distinction between faults and non-faults is more obvious in supercharged and stable operating conditions, the corresponding engine operating condition information satisfies the diagnostic conditions including that the engine intake flow value is within the flow threshold range; the engine intake flow rate The change value is within the range of the change threshold; the engine speed is within the preset speed range; the boost pressure is greater than the boost threshold. Furthermore, in this embodiment, the flow threshold range of the engine intake flow value is preferably that the intake flow is greater than 110kg/h and less than 190kg/h; the change threshold range of the intake flow change is preferably greater than - 20kg/h, less than 30kg/h; the preset speed range of the engine speed may preferably be greater than 1800rpm and less than 2900rpm; the supercharging threshold of the supercharging pressure may be specifically preferably greater than 1200hpa.

In an embodiment, the preferred working information of the pressure sensor may be, for example, whether the working voltage of the pressure sensor 6 is within the working voltage range. It is understandable that the failure of the PCV sensor circuit will lead to an error in the pressure measurement value, so it is necessary to detect the failure of the PCV pressure sensor 6 and suppress the diagnosis of the disconnection of the crankcase ventilation pipeline, that is, there is no related failure suppression for the pressure sensor 6, so as to confirm The pressure sensor 6 is in normal working condition.

Step S2: When the current working condition satisfies the diagnosis condition, obtain the pressure value in the ventilation pipe of the crankcase, and correspond to the obtained relative pressure amplitude according to the pressure value.

In one embodiment, in step S2: when the current working condition satisfies the diagnostic condition, the step of acquiring diagnostic information includes: when the current working condition meets the diagnostic condition, acquiring a plurality of pressure values according to a preset frequency; calculating the adjacent Pressure sample difference between two pressure values; determine whether the pressure sample difference is greater than 0: if yes, assign the new pressure value of the two pressure values to the pressure wave peak value; if not, assign the new pressure value of the two pressure values The pressure value is assigned to the pressure trough value; after each assignment, the difference between the current pressure wave peak value and the current pressure trough value is calculated to obtain the corresponding relative pressure amplitude, and the relative pressure amplitude is saved.

In one embodiment, specifically, the preset frequency is preferably 10 ms, that is, the PCV pressure sensor 6 reads the pressure value ppcv in the crankcase ventilation pipe 3 at a sampling frequency of 10 ms. Calculate the pressure sample difference dppcv between two adjacent new and old pressure values, where the new pressure value is ppcv_new and the old pressure value is ppcv_old, that is, dppcv=ppcv_new-ppcv_old. Determine whether the pressure sample difference dppcv is greater than 0: if dppcv>0, assign the new pressure value ppcv_new to the pressure wave peak ppcvp; if dppcv≤0, assign the new pressure value ppcv_new to the pressure valley value ppcvv. Calculate the difference between the current pressure wave peak value ppcvp and the current pressure valley value ppcvv after each assignment to obtain the corresponding relative pressure amplitude ppcvamptmp_w, that is to say: ppcvamptmp_w=ppcvp-ppcvv, and save the relative pressure amplitude ppcvamptmp_w, so that Read later. Specifically, as a simple example, if a total of 5 pressure value ppcv samples are obtained from t=1 to t=5 according to the preset frequency: 3, 4, 5, 2, 1. Since two pressure values, old and new, are needed for calculation, the calculation starts from t=2. At this time, ppcv_new2=4 and ppcv_old2=3, the pressure sample difference dppcv2=1 at t=2 can be obtained. Since dppcv2>0, the new pressure value ppcv_new2 at t=2 is assigned to the pressure valley value ppcvv2=4 at t=2. Similarly, when t=3, ppcvv3=5, since there is no pressure wave peak ppcvp at this time, the relative pressure amplitude ppcvamptmp_w is not calculated. At t=4, the pressure valley value ppcvv4=ppcv_new4=2 can be obtained through calculation, and the current pressure peak value is the peak value ppcvp3=5 at t=3, and the relative pressure amplitude ppcvamptmp_w4=3 can be obtained by subtracting the two , and save the value. At t=5, the pressure valley value ppcvv5=1 can be obtained similarly. Then calculate the difference between the adjacent pressure peak ppcvp and pressure valley ppcvv at this time, where the pressure valley value ppcvv5 at t=5 has been updated compared with ppcvv4 at t=4, so the current t= The relative pressure amplitude ppcvamptmp_w5 at 5 o'clock needs to be calculated by using the current pressure peak value ppcvv3 and the current pressure valley value ppcvv5 to obtain the current relative pressure amplitude ppcvamptmp_w5=4. Among them, two relative pressure amplitudes were obtained in the five samplings, both of which need to be preserved. Specifically, the values corresponding to the time t, the pressure value ppcv, the pressure peak value ppcvp, the pressure valley value ppcvv, etc. in the cases exemplified in this embodiment can be referred to in Table 3.

The sampling and corresponding calculation results listed in Table 3

In one embodiment, it should be noted that the whole step S2 is performed to obtain and store the relative pressure amplitude ppcvamptmp_w. Subsequent diagnosis is also carried out for the relative pressure amplitude ppcvamptmp_w. In the follow-up, due to the problem of cycle extraction, the initial stage of step S2 for obtaining the relative pressure amplitude ppcvamptmp_w is executed when the current working condition meets the diagnosis conditions. That is to say, in this embodiment, the relative pressure amplitude ppcvamptmp_w can be calculated and stored only when the current working condition satisfies the corresponding conditions; however, the pressure value ppcv can be acquired by the pressure sensor 6 Therefore, the pressure value ppcv can be obtained all the time and the relative pressure amplitude ppcvamptmp_w can be calculated and obtained, and the relative pressure amplitude ppcvamptmp_w will be stored only when the current working condition meets the diagnostic conditions. It can be understood that the above explanation does not limit the specific implementation of when to obtain the pressure value ppcv and calculate and store the relative pressure amplitude ppcvamptmp_w, as long as the relative pressure amplitude ppcvamptmp_w can be recorded within a valid time period can be.

Step S3: Execute relative pressure amplitude processing to obtain the maximum value of relative pressure amplitude.

In one embodiment, in step S3: performing relative pressure amplitude processing to obtain the maximum value of relative pressure amplitude, it includes: when the current working condition does not meet the diagnosis condition, the control timer stops counting; when the current working condition meets When diagnosing the condition, control the timer to start counting; judge whether the accumulated time counted by the timer reaches the preset duration; if so, obtain all relative pressure amplitudes within the accumulated time counted by the timer to obtain the maximum relative pressure amplitude, The timer is reset.

In one embodiment, in this embodiment, when the vehicle operating condition satisfies the diagnosis condition, the relative pressure amplitude ppcvamptmp_w is uniformly standardized, so that it can clearly distinguish between faults and non-faults during the diagnosis process. That is to say, the judgment condition is based on whether the current working condition meets the diagnosis condition, if so, the timer is controlled to start timing; if not, the timing is not performed or stopped. When the accumulated time counted by the timer reaches the preset duration, the preset duration may preferably be 5s, that is, it is judged whether the accumulated time counted by the timer reaches 5s. What needs to be paid attention to is that when the judgment conditions are not met, the timer does not count, that is to say, the actual accumulated timing of the 5s is not necessarily continuous, or the corresponding time of timing is the current working condition conditions that meet the diagnostic criteria. Afterwards, if the cumulative timing duration reaches 5s, obtain all relative pressure amplitudes ppcvamptmp_w in the cumulative time counted by the timer, and count the maximum value of the relative pressure amplitude ppcvamptmp in the crankcase vent pipe 3 within 5s, that is, the maximum value of the pressure amplitude ppcvampds( 1); If the timer cannot reach 5s, the pressure amplitude will not be processed. Among them, if the accumulated timing reaches the preset duration, the timer resets to zero and waits for the cycle corresponding to the next preset duration, that is, if the timer resets to zero, the pressure in the next 5s cycle will be counted again Amplitude maximum ppcvampds(n). Wherein, similarly, all the maximum values of the pressure amplitude ppcvampds(n) will be stored, so as to be extracted for unified analysis in the subsequent diagnosis process.

Step S4: Comparing all relative pressure amplitude maximum values within a driving cycle with diagnostic standard values.

In one embodiment, in step S4: in the step of comparing all relative pressure amplitude maximum values within one driving cycle with diagnostic standard values, the diagnostic standard values include fault thresholds and repair thresholds: the aforementioned step of comparing with the diagnostic standard , including: if there is a maximum value of the relative pressure amplitude smaller than the fault threshold, the count of the fault counter is increased by 1; if there is a maximum value of the relative pressure amplitude greater than the repair threshold, the count of the non-fault counter is increased by 1.

In one embodiment, after a driving cycle, that is, after the vehicle completes the complete process of ignition, running, and flameout, all the maximum pressure amplitude values ppcvampds(n) in the entire process are extracted and analyzed. The main analysis process is to compare the maximum value of the pressure amplitude ppcvampds(n) with the diagnostic standard finger, where the diagnostic standard value includes: fault threshold and repair threshold. As for the specific values of the fault threshold and the repair threshold, preferably, the fault threshold is 4hPa; the repair threshold is 12hPa. For all the maximum pressure amplitude ppcvampds(n) in a driving cycle, compare them with the fault threshold and repair threshold one by one, if there is a maximum pressure amplitude ppcvampds(n) less than or equal to the fault threshold 4hPa, then the fault counter counts up by 1; If there is a maximum value of the pressure amplitude ppcvampds(n) greater than or equal to the repair threshold 12hPa, the non-fault counter counts up by 1. Among them, the specific values for the fault threshold and the repair threshold are the preferred results obtained through the test of this method after the experiment. Specifically, you can refer to Figure 3a, which is the drop point diagram of the test results of the amplitude method provided by the first embodiment of the present invention . It can be seen that a large number of points fall in the range greater than 12hPa, and a small amount fall in the range less than 4hPa, so it is preferable to consider that the points greater than 12hPa belong to the normal state, and the points less than 4hPa belong to the fault state, in the range of 4 to 12hPa It is speculated that it is a false positive diagnosis. It can be seen that the fault threshold value of 4hPa and the repair threshold value of 12hPa are the preferred results obtained through experiments. In practice, they are not necessarily limited to the values exemplified in this embodiment, and can be adjusted accordingly according to different vehicles.

Step S5: Diagnose according to the comparison result, and output the diagnosis result.

In one embodiment, in step S5: performing diagnosis according to the comparison result, and outputting the diagnosis result, including: when the sum of the non-fault counter and the fault counter meets the counting threshold, comparing the count values of the non-fault counter and the fault counter Size; when the value of the fault counter is greater than the non-fault counter, output a fault warning; when the value of the fault counter is less than the non-fault counter, output repair fault prompt information or no fault prompt information.

In one embodiment, after step S4 is executed, since the non-fault counter and the fault counter have technology respectively, when the two only sum the counting threshold, the technology threshold is preferably 5, that is, when the non-fault counter and the fault When the sum of the counters is equal to 5, compare the size of the non-fault counter and the fault counter: if the fault counter is greater than the non-fault counter, then output a shedding fault warning, that is, there is a shedding fault in the high-load pipeline (near the crankcase end); if the fault counter is less than If there is no fault counter, then output repair fault prompt information or no fault prompt information. Specific output methods may include, but are not limited to, corresponding indicator lights or notification of corresponding information to users or maintenance personnel in ways that are not limited to text and voice through output equipment such as screens and speakers. It can be understood that the counting threshold and the output of the diagnosis result are simple enumeration processes in this embodiment, which is not a technical limitation, and corresponding modifications can be made according to specific situations in actual implementation.

In one embodiment, compared with the energy value method, the present invention does not need to calibrate the model pressure of the crankcase ventilation system under different engine operating conditions according to the test vehicle, so as to reduce the influence of vehicle differences on the calibration data. According to the actual pressure measured by the PCV pressure sensor 6 Value ppcv The maximum value of the pressure amplitude ppcvampds(n) obtained after processing ppcv distinguishes faulty and non-faulty states. It can achieve extremely low false alarm probability and high robustness. According to the statistical analysis of 3 Sigma, the energy value method adopted by the normal pipeline near the air filter end, the current fault threshold is 0.68, and the false alarm fault risk rate is 5‰ (normal distribution (μ=0.14, σ=0.21) is greater than 0.68 probability); the normal pipeline adopts the amplitude method adopted in the present invention near the crankcase end, and the fault threshold is 4hpa at present, and the false alarm fault risk is 1.3‰ (normal distribution (μ=20.12, σ=5.36) less than 4hpa probability), the false positive rate has been reduced by nearly 3/4. For details, reference may be made to FIG. 3a to FIG. 4b. In general, the specific implementation process of the method for diagnosing the crankcase ventilation pipeline disconnection provided by the first embodiment of the present invention can be referred to in FIG. Among them, the diagnostic conditions in step S2 have been given in detail in Figure 5, and the specific values of the fault threshold and repair threshold included in the diagnostic standard value of S4, so in Figure 5 it is the preferred situation of this embodiment, the actual Each value of the diagnostic conditions and the diagnostic standard value are not limited to the examples in the figure, and can be adjusted accordingly according to the actual situation.

The method for diagnosing the disconnection of the crankcase ventilation pipe provided by the first embodiment of the present invention includes the following steps: step S1: obtain the current working condition of the vehicle; step S2: obtain the pressure in the crankcase ventilation pipe when the current working condition meets the diagnostic conditions value, and corresponding to the obtained relative pressure amplitude according to the pressure value; step S3: execute relative pressure amplitude processing to obtain the maximum value of relative pressure amplitude; step S4: compare all relative pressure amplitude maximum values within a driving cycle with diagnostic standard values Comparison; Step S5: Diagnose according to the comparison result, and output the diagnosis result. Therefore, the present invention can distinguish the state of whether the pipeline falls off according to the "pressure fluctuation in the crankcase ventilation pipe", so as to meet the purpose of diagnosis. Compared with the prior art, the false alarm rate is greatly reduced and the robustness is improved. It brings guiding significance to the diagnosis of pipeline shedding when the pressure sensor is installed, greatly reduces the false alarm rate, reduces the time and human resources of calibration work, reduces the user's operation, increases the convenience of the user, and improves the use of the user experience.

second embodiment

Fig. 6 is a schematic diagram of the first structure of the diagnostic device for the disconnection of the crankcase ventilation pipe provided by the second embodiment of the present invention. In order to clearly describe the diagnostic device 110 for the disconnection of the crankcase ventilation pipe provided by the second embodiment of the present invention, please refer to FIG. 1 and FIG. 6 .

The crankcase ventilation pipeline fall-off diagnosis device 110 provided by the second embodiment of the present invention includes at least: a processor A101 and a memory A201, wherein the processor A101 is used to execute the computer program A6 stored in the memory A201 to realize the first The steps of the method for diagnosing the disconnection of the crankcase ventilation pipeline described in the embodiment.

In one implementation, the diagnostic device 110 for disconnection of the crankcase ventilation pipe provided in this embodiment includes at least one processor A101 and at least one memory A201. Wherein, at least one processor A101 may be called a processing unit A1, and at least one memory A201 may be called a storage unit A2. Specifically, the storage unit A2 stores a computer program A6, and when the computer program A6 is executed by the processing unit A1, the crankcase ventilation pipeline fall-off diagnosis device 110 provided in this embodiment realizes the crankcase as described in the first embodiment. Steps in the method for diagnosing ventilation line dislodgement. For example, step S1 shown in Figure 1: obtain the current working condition of the vehicle; step S2: when the current working condition satisfies the diagnosis condition, obtain the pressure value in the ventilation pipe of the crankcase, and correspond to the obtained relative pressure amplitude according to the pressure value; Step S3: Perform relative pressure amplitude processing to obtain the maximum relative pressure amplitude; Step S4: Compare all relative pressure amplitude maximum values within a driving cycle with diagnostic standard values; Step S5: Diagnose according to the comparison results, and output diagnostic result.

In one implementation, the diagnostic device 110 for disconnection of the crankcase ventilation pipe provided in this embodiment may include multiple memories A201 (referred to as storage units A2 for short).

Wherein, the storage unit A2 may be a volatile memory or a non-volatile memory, and may also include both volatile and non-volatile memories. Wherein, the non-volatile memory can be a read-only memory (ROM, Read Only Memory), a programmable read-only memory (PROM, Programmable Read-Only Memory), an erasable programmable read-only memory (EPROM, Erasable Programmable Read-Only Memory), Only Memory), Electrically Erasable Programmable Read-Only Memory (EEPROM, Electrically Erasable Programmable Read-Only Memory), Magnetic Random Access Memory (FRAM, ferromagnetic random access memory), Flash Memory (Flash Memory), Magnetic Surface Memory , CD, or CD-ROM (CD-ROM, Compact Disc Read-Only Memory); the magnetic surface storage can be disk storage or tape storage. The volatile memory may be random access memory (RAM, Random Access Memory), which is used as an external cache. By way of illustration and not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM, Static Random Access Memory), Synchronous Static Random Access Memory (SSRAM, Synchronous Static Random Access Memory), Dynamic Random Access Memory Memory (DRAM, Dynamic Random Access Memory), Synchronous Dynamic Random Access Memory (SDRAM, Synchronous Dynamic Random Access Memory), Double Data Rate Synchronous Dynamic Random Access Memory (DDRSDRAM, Double Data Rate Synchronous Dynamic Random Access Memory), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM, Enhanced Synchronous Dynamic Random Access Memory), Synchronous Link Dynamic Random Access Memory (SLDRAM, SyncLink Dynamic Random Access Memory), Direct Memory Bus Random Access Memory (DRRAM, Direct Rambus Random Access Memory) . The memory unit A2 described in the embodiment of the present invention is intended to include but not limited to these and any other suitable types of memory.

In one embodiment, the storage unit A2 preferably stores the method for diagnosing the disconnection of the crankcase ventilation pipeline provided by the first embodiment of the present invention. Furthermore, the value of the pressure value ppcv obtained by the pressure sensor 6 may also be temporarily stored, and the series of values obtained correspondingly by the processor A101 such as the pressure sample difference dppcv, the pressure peak value ppcvp, the pressure valley value ppcvv, the relative The pressure amplitude ppcvamptmp_w and finally the maximum pressure amplitude ppcvampds(n) for diagnostic purposes. When the processor A101 needs to perform calculation or read for diagnosis, it can read the corresponding value stored in the previous execution steps from the storage unit A2.

In one embodiment, the diagnostic device 110 for the disconnection of the crankcase ventilation line may further include a bus connecting different components (such as the processor A101 and the memory A201, the output device A3, etc.). Among them, the output device A3 can output the corresponding diagnosis result after the diagnosis is completed. The specific output device may include but not limited to the display device showing the diagnosis result to the user in the form of graphics and text; display; it can also be an icon display device, by displaying the corresponding icon, such as the fault icon on the vehicle dashboard to prompt the user, and it can also be more concise as the corresponding indicator light, for example, the red indicator light corresponds to the failure warning of falling off, and the yellow indicator light corresponds to Repair fault prompt information, green corresponds to no fault prompt information, etc. Wherein, for the above output device, it can be one of the examples, or any combination of two or more, and there is no specific limitation to this. The example is only a description of the technology, as long as it can be divisible to the user. Any device that diagnoses the results is acceptable.

In an embodiment, the crankcase ventilation pipeline fall-off diagnosis device 110 in this embodiment may further include a communication interface (such as an I/O interface A4 ), which may be used to communicate with external devices. For example, as shown in the figure, the output device A3 is connected to the processor A101 through the I/O interface A4, serving as an intermediary and bridge for data transmission.

In one embodiment, the I/O interface A4 may be connected to the vehicle can bus to obtain information on the current working condition of the vehicle, so that the processor A101 can determine whether the working condition of the vehicle meets the diagnostic conditions for diagnosis.

In an embodiment, the crankcase ventilation pipeline fall-off diagnosis device 110 provided in this embodiment may further include a communication device A5. Specifically, after the diagnosis is completed, the communication device A5 may output the diagnosis result to other terminals associated with the crankcase ventilation pipe disconnection diagnosis device 110 . Specifically, the technologies used in the communication connection include but are not limited to wireless and wired communication technologies. Furthermore, for wired communication technologies, it may include but not limited to Ethernet (Ethernet, ETH), M-BUS, Power Line Communication (Power Line Communication, PLC), Universal Serial Bus (Universal Serial Bus, USB), RS -485, RS-232, etc.; for wireless communication technologies, including but not limited to Global System for Mobile Communication (GSM), Enhanced Data GSM Environment (EDGE), broadband code division Multiple access technology (wideband codedivision multiple access, W-CDMA), code division multiple access technology (Code division access, CDMA), time division multiple access technology (time division multiple access, TDMA), Bluetooth, wireless fidelity technology (Wireless, Fidelity , WiFi) (such as IEEE 802.11a, IEEE802.11b, IEEE802.11g and/or IEEE 802.11n), VoIP (Voice over internet protocol, Worldwide Interoperability for Microwave Access, Wi-Max), other protocols for mail, instant messaging, and short messages, and any other suitable communication protocols, even those that have not yet been developed. The specific implementation method can be that after the user turns off the engine, the crankcase ventilation pipeline disconnection diagnosis device 110 executes and completes the diagnosis, and sends the diagnosis result to the user's mobile terminal or the maintenance terminal of the maintenance personnel through the communication device A5, so that the user can Or the maintenance personnel can check the diagnostic results through the corresponding terminal, without the trouble of obtaining it through the diagnostic device 110 for the disconnection of the crankcase ventilation pipe installed in the vehicle.

The crankcase ventilation pipeline fall-off diagnosis device 110 provided by the second embodiment of the present invention includes a memory A101 and a processor A201, and the processor A101 is used to execute the computer program A6 stored in the memory A201 to realize the operation as described in the first embodiment. The steps of the method for diagnosing the disconnection of the crankcase ventilation pipeline, therefore, the diagnostic device 110 for the disconnection of the crankcase ventilation pipeline provided in this embodiment can distinguish the state of whether the pipeline is disconnected according to the "pressure fluctuation in the crankcase ventilation pipeline", so as to meet the purpose of diagnosis . Compared with the prior art, the false alarm rate is greatly reduced and the robustness is improved. It brings guiding significance to the diagnosis of pipeline shedding when the pressure sensor is installed, greatly reduces the false alarm rate, reduces the time and human resources of calibration work, reduces the user's operation, increases the convenience of the user, and improves the use of the user experience.

The second embodiment of the present invention also provides a vehicle, including the diagnostic device 110 for the disconnection of the crankcase ventilation pipe provided by the second embodiment of the present invention.

In one embodiment, the specific installation method for the diagnostic device 110 for the falling off of the crankcase ventilation line may include but not limited to be a separate device in the vehicle; it may also be a unit in the PCV system, that is, included in the PCV system ; It can also be a functional module in the vehicle-mounted terminal, and all embodiments can be executed correspondingly by the vehicle-mounted terminal in the vehicle. It can be understood that the above examples are technical descriptions, and actual placement conditions may not be limited to the above examples.

The second embodiment of the present invention also provides a computer-readable storage medium, the computer-readable storage medium stores a computer program A6, and when the computer program A6 is executed by the processor A101, the crankcase as described in the first embodiment is realized. Steps in the method for diagnosing ventilation line dislodgement.

In one embodiment, the computer-readable storage medium provided by this embodiment may include any entity or device or recording medium capable of carrying computer program codes, such as ROM, RAM, magnetic disk, optical disk, flash memory, and the like.

The technical effects that can be achieved when the computer program A6 stored in the computer-readable storage medium provided by the second embodiment of the present invention is executed by the processor A101 have been described in detail above, and will not be repeated here.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

It should be noted that, in this document, the term "comprising", "comprising" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, It also includes other elements not expressly listed, or elements inherent in the process, method, article, or device. Without further limitations, an element defined by the statement "comprising a..." does not exclude the presence of other identical elements in the process, method, article, or device that includes the element. In addition, different implementations of the present application Components, features, and elements with the same name in the example may have the same meaning, or may have different meanings, and the specific meaning shall be determined based on the explanation in the specific embodiment or further combined with the context in the specific embodiment. In this article, unless otherwise specified, the meanings of "plurality" and "several" are two or more.

It should be understood that although the various steps in the flow chart in the embodiment of the present application are displayed sequentially as indicated by the arrows, these steps are not necessarily executed sequentially in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the figure may include multiple sub-steps or multiple stages, these sub-steps or stages are not necessarily executed at the same time, but may be executed at different times, and the execution order is not necessarily sequential Instead, it may be performed alternately or alternately with at least a part of other steps or sub-steps or stages of other steps.

Those of ordinary skill in the art can understand that all or part of the steps for implementing the above method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the The steps of the above method embodiments are included. The foregoing storage medium includes: various media capable of storing program codes such as ROM, RAM, magnetic disk or optical disk.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. Should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (7)

1. A method for diagnosing the falling-off of a crankcase ventilation pipeline is characterized by comprising the following steps:

acquiring the current working condition of the vehicle;

when the current working condition meets the diagnosis condition, acquiring a pressure value in the crankcase ventilation pipe, and correspondingly acquiring a relative pressure amplitude according to the pressure value;

when the current working condition does not meet the diagnosis condition, the timer is controlled to stop timing; when the current working condition meets the diagnosis condition, a timer is controlled to start timing; judging whether the accumulated time counted by the timer reaches a preset duration or not; if yes, acquiring all the relative pressure amplitudes in the accumulated time counted by the timer to obtain the maximum value of the relative pressure amplitudes, and resetting the timer;

comparing all of said relative pressure amplitude maxima within a drive cycle to diagnostic criteria; the diagnosis standard value comprises a fault threshold value and a repair threshold value; if one of the relative pressure amplitude maxima is less than the fault threshold, the fault counter counts up by 1; if one of the maximum values of the relative pressure amplitude is greater than the repair threshold, the fault-free counter counts by 1;

When the sum of the fault counter and the fault counter meets a counting threshold value, comparing the counting numerical values of the fault counter and the fault counter; outputting a drop fault warning when the fault counter value is greater than the no fault counter; and outputting repair fault prompt information or no fault prompt information when the fault counter value is smaller than the no fault counter value.

2. The crankcase ventilation conduit disconnection diagnosing method according to claim 1, wherein the step of acquiring the current operating condition of the vehicle includes:

acquiring current temperature information, wherein the current temperature information comprises an ambient temperature, a current engine coolant temperature and a delay time;

acquiring current engine working condition information, wherein the engine working condition information comprises an engine air inlet flow value, an engine air inlet flow change value, an engine rotating speed and a supercharging pressure;

and acquiring the current working information of the pressure sensor.

3. The crankcase ventilation line sloughing diagnostic method of claim 2, the diagnostic conditions comprising:

when the ambient temperature is higher than a preset temperature threshold, and the delay time reaches a first time threshold; or when the ambient temperature is lower than a preset temperature threshold, the temperature of the engine coolant reaches a corresponding coolant temperature threshold, and the corresponding delay time reaches a second time threshold;

The engine intake air flow value is within a flow threshold range;

the engine intake air flow change value is in a change threshold range;

the engine speed is within a preset speed range;

the boost pressure is greater than a boost threshold;

the working information of the pressure sensor accords with normal working conditions.

4. The crankcase ventilation line dropout diagnosis method according to claim 1, wherein the step of acquiring diagnosis information when the current operating condition satisfies a diagnosis condition includes:

when the current working condition meets the diagnosis condition, acquiring a plurality of pressure values according to a preset frequency;

calculating a pressure sample difference value of two adjacent pressure values;

judging whether the pressure sample difference value is larger than 0:

if yes, assigning a new pressure value in the two pressure values to a pressure wave peak value;

if not, assigning a new pressure value in the two pressure values to a pressure trough value;

and calculating the difference between the current pressure wave peak value and the current trough value after each assignment to obtain the corresponding relative pressure amplitude, and storing the relative pressure amplitude.

5. A crankcase ventilation line dropout diagnostic device comprising a processor and a memory:

The processor is configured to execute a computer program stored in the memory to implement the crankcase ventilation conduit sloughing diagnostic method steps of any one of claims 1 to 4.

6. A vehicle comprising the crankcase ventilation line dropout diagnostic device according to claim 5.

7. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program which, when executed by a processor, implements the steps of the crankcase ventilation line fall-off diagnosis method according to any one of claims 1 to 4.