CN115217624A - Crankcase ventilation pipeline falling-off diagnosis method and device, vehicle and storage medium - Google Patents
Crankcase ventilation pipeline falling-off diagnosis method and device, vehicle and storage medium Download PDFInfo
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Abstract
The invention belongs to the technical field of vehicles, and relates to a crankcase ventilation pipeline falling diagnosis method, a crankcase ventilation pipeline falling diagnosis device, a vehicle and a computer readable storage medium. The crankcase ventilation pipeline falling diagnosis method 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 a crankcase ventilation pipe, and correspondingly acquiring a relative pressure amplitude according to the pressure value; performing relative pressure amplitude processing to obtain a relative pressure amplitude maximum value; comparing all relative pressure amplitude maxima within a driving cycle with diagnostic criteria; and diagnosing according to the comparison result and outputting a diagnosis result. Therefore, the method can greatly reduce the probability of diagnosis false alarm, has high robustness, brings instructive significance for pipeline falling diagnosis of the pressure sensor, and reduces the time and manpower resources of calibration work.
Description
Technical Field
The invention belongs to the technical field of vehicles, and particularly relates to a crankcase ventilation pipeline falling diagnosis method, a crankcase ventilation pipeline falling diagnosis device, a vehicle and a computer readable storage medium.
Background
During operation of the engine, unburned gas in the cylinder may blow into the crankcase through a gap between the piston and the cylinder liner. The function of a crankcase ventilation (PCV) system isThe unburned air-fuel mixture blown into the crankcase is reintroduced into the cylinder for combustion. However, because the pipeline between the PCV valve and the air filtered air inlet pipe is connected in a clamping mode of two clamps, the risk that the clamp loosens and the pipeline falls off exists, and the unburned mixer enters the atmosphere to cause the evaporative emission to exceed the standard. The method comprises the following steps of carrying out fault diagnosis on pipeline falling and formulating a fault management mechanism, wherein an energy value method is generally adopted in the prior art: recording the measured pressure p in the crankcase ventilation duct 1 And p is 1 Converting the energy value into an energy value and accumulating; meanwhile, calculating model pressure p in a crankcase ventilation pipe according to the current engine speed and engine load 2 And p is 2 And converting the energy value into an energy value and then accumulating the energy value. Calculating p 1 And p 2 The deviation dppcv between the cumulative values, the calculation formula for dppcv is as follows:
in the formula, enegy (p) 1 ) Is the energy value of the measured pressure; ene gy (p) 2 ) Is the energy value of the model pressure. Energy (p) when high load vent pipe is disconnected 1 )≈0，enegy(p 2 ) Unchanged, dppcv is approximately equal to 1; energy (p) when a high-load ventilation pipe connection is normal 1 )≈enegy(p 2 )，dppcv≈0。
However, the energy value method has two disadvantages: 1. the currently adopted diagnosis scheme is used for diagnosing the shedding faults at two ends of the high-load ventilation pipeline at the same time, and because the energy ratio dppcv calculated by shedding close to the end of the air inlet pipe is large (about 0.99) and the energy ratio calculated by shedding close to the PCV valve is small (about 0.8), in order to prevent faults from being reported, the setting of a fault threshold value is smaller than 0.8, and the risk of false fault reporting is increased. 2. The existing diagnosis scheme adopts the 'actual pressure' of a crankcase ventilation pipe and the 'model pressure' ratio calibrated according to a calibrated vehicle to make judgment, the actual pressure 'is only less than 1Kpa under partial diagnosis working conditions and is greatly influenced by vehicle difference and PCV pipeline hardware difference, the coverage of the model pressure' on the vehicle difference is insufficient, and when the 'actual pressure' absolute value is smaller than the 'model pressure' absolute value, dppcv approaches 1, so that the risk of false-alarm faults is increased. How to solve the defect that the current diagnosis scheme is insufficient in vehicle difference coverage and prone to false fault diagnosis so as to meet the purpose of diagnosis is an urgent problem to be solved.
In response to the above problems, those skilled in the art have sought solutions.
The foregoing description is provided for general background information and does not necessarily constitute prior art.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a crankcase ventilation pipeline drop diagnosis method, a crankcase ventilation pipeline drop diagnosis device, a vehicle and a computer readable storage medium, which can distinguish whether a pipeline drops according to 'pressure fluctuation in a crankcase ventilation pipe' so as to meet the diagnosis purpose. Therefore, compared with an energy value method, the method does not need to calibrate the model pressure of the crankcase ventilation system under different engine working conditions according to the test vehicle, reduces the influence of vehicle difference on calibration data, and distinguishes fault and non-fault states according to the pressure amplitude after the pressure processing is actually measured by the PCV pressure sensor. The false alarm probability is extremely low, and the robustness is high. The method brings guiding significance for diagnosing the pipeline falling of the pressure sensor, greatly reduces the false alarm rate and simultaneously reduces the time and human resources of calibration work.
The technical problem to be solved by the invention is realized by adopting the following technical scheme:
the invention provides a crankcase ventilation pipeline falling diagnosis method, which 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 a crankcase ventilation pipe, and correspondingly acquiring a relative pressure amplitude according to the pressure value; performing relative pressure amplitude processing to obtain a relative pressure amplitude maximum value; comparing all relative pressure amplitude maxima within a driving cycle with diagnostic criteria; and diagnosing according to the comparison result and outputting a diagnosis result.
Further, the step of obtaining 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 delay time; acquiring current engine working condition information, wherein the engine working condition information comprises an engine intake flow value, an engine intake flow change value, an engine rotating speed and a supercharging pressure; and acquiring the current working information of the pressure sensor.
Further, the aforementioned diagnostic conditions include: when the ambient temperature is higher than a preset temperature threshold, and the delay time reaches a first time threshold; or when the environmental 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 air flow variation value is within a variation threshold range; the rotating speed of the engine is within a preset rotating speed range; the boost pressure is greater than a boost threshold; the working information of the pressure sensor accords with the normal working condition.
Further, when the current operating condition satisfies the diagnosis condition, the step of obtaining the diagnosis information includes: when the current working condition meets the diagnosis condition, acquiring a plurality of pressure values according to a preset frequency; calculating the pressure sample difference value of two adjacent pressure values; judging whether the pressure sample difference value is larger than 0: if so, assigning a new pressure value of the two pressure values to the pressure wave peak value; if not, assigning a new pressure value of the two pressure values to the pressure wave valley value; and calculating the difference value between the current pressure wave peak value and the current pressure wave valley value after each assignment to obtain the corresponding relative pressure amplitude, and storing the relative pressure amplitude.
Further, the step of performing relative pressure amplitude processing to obtain a maximum value of the relative pressure amplitude includes: when the current working condition does not meet the diagnosis condition, controlling a timer to stop timing; when the current working condition meets the diagnosis condition, controlling a timer to start timing; judging whether the accumulated time timed by the timer reaches a preset time length or not; if yes, all relative pressure amplitudes in the accumulated time timed by the timer are obtained to obtain the maximum value of the relative pressure amplitudes, and the timer is reset.
Further, in the step of comparing all maximum values of relative pressure amplitude in one driving cycle with the diagnostic criterion values, the diagnostic criterion values include a failure threshold value and a repair threshold value: the aforementioned step of comparing to a diagnostic standard, comprising: if a maximum value of the relative pressure amplitude is smaller than the fault threshold value, adding 1 to the count of the fault counter; if there is a maximum value of the relative pressure amplitude greater than the repair threshold, the no fault counter counts up by 1.
Further, the step of diagnosing based on 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 value, comparing the counting numerical values of the non-fault counter and the fault counter; when the value of the fault counter is larger than that of the fault-free counter, outputting a drop-out fault warning; and when the numerical value of the fault counter is smaller than that of the fault-free counter, outputting repair fault prompt information or fault-free prompt information.
The invention also provides a crankcase ventilation pipeline falling diagnosis device which is characterized by comprising a processor and a memory: the processor is configured to execute a computer program stored in the memory to implement the steps of the crankcase ventilation circuit disengagement diagnostic method as described above.
The invention also provides a vehicle which comprises the crankcase ventilation pipeline falling-off diagnosis device.
The invention also provides a computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method for diagnosing a crankcase ventilation line dropout as described above.
The invention also provides a crankcase ventilation pipeline falling diagnosis method, a crankcase ventilation pipeline falling diagnosis device, a vehicle and a computer readable storage medium. The crankcase ventilation pipeline falling diagnosis method 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 a crankcase ventilation pipe, and correspondingly acquiring a relative pressure amplitude according to the pressure value; performing relative pressure amplitude processing to obtain a relative pressure amplitude maximum value; comparing all relative pressure amplitude maxima within a driving cycle with diagnostic criteria; and diagnosing according to the comparison result and outputting a diagnosis result. Therefore, the invention can distinguish whether the pipeline falls off according to the pressure fluctuation in the ventilation pipe of the crankcase so as to meet the purpose of diagnosis. Compared with the prior art, the method greatly reduces the false alarm rate and improves the robustness. The method brings guiding significance for pipeline falling diagnosis of the pressure sensor, greatly reduces the false alarm rate, simultaneously reduces the calibration work time and human resources, reduces the operation of a user, increases the convenience of the user, and improves the use experience of the user.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are specifically illustrated in the accompanying drawings and described in detail.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic flow chart of a crankcase ventilation pipeline falling-off diagnosis method according to a first embodiment of the invention;
FIG. 2 is a simplified schematic illustration of a PCV system configuration;
fig. 3a is a drop-point diagram of the test result of the amplitude method provided by the first embodiment of the present invention;
FIG. 3b is a3 sigma statistical chart of the false positive fault risk of the amplitude method according to the first embodiment of the present invention;
FIG. 4a is a plot of energy value method test results;
FIG. 4b is a3 sigma statistical diagram of the false alarm fault risk of the energy method;
FIG. 5 is a flowchart illustrating a method for diagnosing a crankcase ventilation circuit disengagement in accordance with a first embodiment of the invention;
fig. 6 is a schematic structural diagram of a crankcase ventilation pipeline falling-off diagnostic device according to a second embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiments of the present invention will be described in detail with reference to the accompanying drawings.
First embodiment
FIG. 1 is a schematic flow diagram of a crankcase ventilation circuit disengagement diagnostic method according to a first embodiment of the invention; FIG. 2 is a simplified schematic illustration of a PCV system configuration; fig. 3a to 3b are graphs showing experimental results of an amplitude method according to a first embodiment of the present invention; fig. 4a to 4b are graphs showing experimental results of an energy value method according to a first embodiment of the present invention. For clearly describing the crankcase ventilation pipeline falling-off diagnosis method provided by the first embodiment of the invention, please refer to fig. 1 to 5.
During operation of the engine, unburned air-fuel mixture in the cylinder may blow into the crankcase through a gap between the piston and the cylinder liner. The function of a crankcase ventilation (PCV) system is to reintroduce the unburned mixture that has entered the crankcase into the cylinder for combustion. The PCV system is shown in FIG. 2. The PCV valve 2 is connected with an air inlet pipe 7 through a crankcase ventilation pipe 3, and two ends of the crankcase ventilation pipe 3 are connected in a clamping manner through clamping bands. In the medium and high load condition, no negative pressure exists in the intake manifold 4, and the negative pressure exists in the air filtered intake pipe 7 at the moment, so that the blow-by gas in the crankcase can be sucked into the intake pipe 7 through the crankcase ventilation pipe 3, and the ventilation pipe is also called a high load ventilation pipe. The pressure sensor 6 is arranged on the high-load vent pipe through the pressure sensor 5, and whether the high-load vent pipe falls off or not can be monitored through the pressure condition in the high-load vent pipe. Therefore, the invention designs a device for diagnosing, controlling and processing the falling of the crankcase ventilation pipeline based on the pressure fluctuation condition in the pipeline. The method for diagnosing the falling of the crankcase ventilation pipeline based on the pressure fluctuation measured by the pressure sensor is provided, so that the OBD function of the crankcase ventilation pipeline is finally realized.
In an embodiment, the crankcase ventilation pipeline falling-off diagnosis method may be applied to a crankcase ventilation pipeline falling-off diagnosis device, specifically, the device may be a functional module of an on-board terminal, and performs diagnosis by acquiring vehicle information, or may be a diagnosis device separately provided in a PCV system, and specifically, the setting and application scenarios are not limited by the technology. Furthermore, the first embodiment of the present invention provides a crankcase ventilation pipeline falling-off diagnosis method, which comprises the following steps:
step S1: and acquiring the current working condition of the vehicle.
In one embodiment, in step S1: the step of obtaining the current working condition of the vehicle comprises the following steps: acquiring current temperature information, wherein the current temperature information comprises an ambient temperature, a current engine coolant temperature and 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 supercharging pressure; and acquiring the current working information of the pressure sensor.
In one embodiment, all the above information obtained from the current operating condition may be roughly divided into three types of information: current temperature information, engine operating condition information, and pressure sensor operating information. Specifically, in the case of the current temperature information, the PCV pressure sensor 6 is at risk of icing due to the lower ambient temperature and/or the lower engine coolant temperature, which affects the accuracy of the acquired pressure value and thus the determination of the diagnostic result. It is therefore necessary to establish that the pressure sensor 6 is not at risk of icing, which corresponds to the ambient temperature of the engine coolant temperature and the delay time. For the working condition of the engine, because the distinction degree of faults and no faults is more obvious in the supercharging and stabilizing working conditions, the engine rotating speed interval, the engine intake flow interval and the engine intake flow gradient interval which enter the diagnosis need to be specified under the supercharging working condition of the engine. Therefore, the engine intake air flow value, the engine intake air flow variation value, the engine speed and the supercharging pressure are required to be correspondingly obtained. Finally, the pressure value collected by the pressure sensor 6 is accurate and effective according to the working information of the pressure sensor, so that the effectiveness of the diagnosis result is ensured.
In one embodiment, the diagnostic conditions comprise: when the ambient temperature is higher than a preset temperature threshold, and the delay time reaches a first time threshold; or when the environmental 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 air flow variation value is within a variation threshold range; the rotating speed of the engine is in a preset rotating speed range; the boost pressure is greater than a boost threshold; the working information of the pressure sensor accords with the normal working condition.
In one embodiment, it is ensured that the pressure sensor 6 is not at risk of icing for the current temperature information, so that for those at risk of icing when the ambient temperature is below a preset temperature threshold, in which case the temperature of the engine coolant needs to reach a certain coolant temperature threshold, and when the corresponding delay time exceeds a second time threshold, a diagnostic operation is performed again to eliminate the influence of the temperature influence on the diagnostic result. It can be understood that the temperature is a variable value in real life, and there is a certain correspondence relationship among the ambient temperature, the coolant temperature, and the delay time, for which, reference may be made to tables 1 and 2.
TABLE 1 relationship between ambient temperature and Engine Coolant temperature
| Ambient temperature (. Degree. C.) | -30 | -9.8 | -6.8 | 0 | 5.3 | 9.8 |
| Temperature of the coolant (. Degree.C.) | 81.8 | 80.3 | 69.8 | 69.8 | 69.8 | 50.3 |
TABLE 2 ambient temperature vs. delay time relationship
| Ambient temperature (. Degree. C.) | -30 | -9.8 | -6.8 | 0 | 5.3 | 9.8 |
| Delay time(s) | 6000 | 4500 | 1500 | 200 | 900 | 300 |
Meanwhile, as can be seen from the table, the highest ambient temperature in the table is 9.8 ℃, that is, the optimal choice for the preset temperature threshold value in this embodiment is 9.8 ℃, that is, when the ambient temperature is higher than 9.8 ℃, it is considered that there is no risk of icing of the pressure sensor 6, and therefore, the coolant temperature does not need to be considered any more, and only the delay time satisfies the optimal corresponding 300s in the table, the diagnosis can be started. When the ambient temperature is lower than 9.8 ℃, the influence of the coolant temperature needs to be considered, and whether the corresponding delay time is met or not needs to be considered, for example, when the ambient temperature is around 0 ℃, the delay time of 1200s after the engine coolant temperature reaches 69.8 ℃ is needed to enter the diagnosis, so that the influence of the icing on the diagnosis is reduced. Wherein, although the writing ambient temperature in the table may be below-30 ℃ below zero, this is for extreme cases, and it is preferred that the ambient temperature is at least 10 ℃ below zero.
In one embodiment, for the embodiment of obtaining the engine operating condition information, the engine operating condition information specifically includes an engine intake air flow value, an engine intake air flow variation value, an engine speed, and a boost pressure. As described above, because the discrimination between the fault and the no-fault is more obvious in the supercharging and stabilizing working conditions, the condition information of the corresponding engine meeting the diagnosis condition includes that the intake air flow value of the engine is in the flow threshold range; the variation value of the engine intake air flow is within the variation threshold range; the rotating speed of the engine is within a preset rotating speed range; the boost pressure is greater than the boost threshold. Further, in the present embodiment, the flow threshold range for the engine intake air flow value is preferably such that the intake air flow is greater than 110kg/h and less than 190kg/h; the variation threshold range of the variation of the air inflow flow is preferably more than-20 kg/h and less than 30kg/h; the preset rotation speed range of the engine rotation speed can be preferably rotation speed more than 1800rpm and less than 2900rpm; the boost threshold of the boost pressure may particularly preferably be required to be greater than 1200hpa.
In one embodiment, the pressure sensor operating information may preferably be, for example, whether the operating voltage of the pressure sensor 6 is within an operating voltage range. It will be appreciated that since a PCV sensor circuit failure can result in erroneous pressure measurements, it is desirable to suppress the crankcase ventilation line drop diagnostic upon detection of a PCV pressure sensor 6 failure, i.e., there is no associated failure suppression for the pressure sensor 6 to confirm that the pressure sensor 6 is in a normal operating condition.
Step S2: and 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.
In one embodiment, in step S2: when the current working condition meets the diagnosis condition, the step of obtaining the diagnosis information comprises the following steps: when the current working condition meets the diagnosis condition, acquiring a plurality of pressure values according to a preset frequency; calculating the pressure sample difference value of two adjacent pressure values; judging whether the pressure sample difference value is larger than 0: if so, assigning a new pressure value of the two pressure values to the pressure wave peak value; if not, assigning a new pressure value of the two pressure values to the pressure wave valley value; and calculating the difference value between the current pressure wave peak value and the current pressure wave valley value after each assignment to obtain the corresponding relative pressure amplitude, and storing the relative pressure amplitude.
In one embodiment, in particular, the preset frequency is preferably 10ms, i.e. the PCV pressure sensor 6 reads the pressure value ppcv in the crankcase ventilation line 3 at a sampling frequency of 10 ms. Calculating a pressure sample difference value dppcv between two adjacent new and old pressure values, wherein the new pressure value is ppcv _ new and the old pressure value is ppcv _ old, namely dppcv = ppcv _ new-ppcv _ old. Judging whether the pressure sample difference value dppcv is larger than 0: if dppcv is greater than 0, assigning the new pressure value ppcv _ new to the pressure wave peak value ppcvp; and if dppcv is less than or equal to 0, assigning the new pressure value ppcv _ new to the pressure wave valley value ppcvv. After each assignment, the difference between the current pressure peak value ppcvp and the current pressure trough value ppcvv is calculated to obtain the corresponding relative pressure amplitude ppcvmptmp _ w, that is to say: ppcvamptmp _ w = ppcvp-ppcvv and saves the relative pressure amplitude ppcvamptmp _ w for subsequent reading. Specifically, as a simple example, if a total of 5 pressure values ppcv samples are obtained from t =1 to t =5 at a predetermined frequency: 3. 4, 5, 2 and 1. Since two new and old pressure values are required to be calculated, the calculation is started from t =2, and at this time, ppcv _ new2=4 and ppcv _ old2=3, the pressure sample difference value dppcv2=1 at t =2 can be obtained. Since dppcv2 > 0, a new pressure value ppcv _ new2 at t =2 is assigned to the pressure trough value ppcvv2=4 at t = 2. Similarly, when t =3, ppcvv3=5, the relative pressure amplitude ppcvtmp _ w is not calculated since the pressure wave peak ppcvp is not yet present. At t =4, the pressure wave trough value ppcvv4= ppcv _ new4=2 is calculated, and the current pressure wave crest value is the wave crest value ppcvp3=5 at t =3, and the relative pressure amplitude ppcvmptmp _ w4=3 is obtained by subtracting the two values, and the value is saved. At t =5, a pressure trough value ppcvv5=1 can be obtained in the same way. Then the difference between the adjacent pressure wave crest ppcvp and the pressure wave trough ppcvv at this time is calculated, wherein the pressure wave trough value ppcvv5 at t =5 is updated compared with the pressure wave trough value ppcvv4 at t =4, so that actually to obtain the current relative pressure amplitude ppcvmptmp _ w5 at t =5, the current pressure wave crest value ppcvv3 and the current pressure wave trough value ppcvv5 need to be calculated to obtain the current relative pressure amplitude ppcvmptmp _ w5=4. In the five sampling, two relative pressure amplitudes are obtained, and both are required to be preserved. Specifically, values corresponding to time t, pressure value ppcv, pressure wave peak value ppcvp, pressure wave valley value ppcvv, and the like in the case exemplified in the present embodiment can be seen in table 3.
The samples listed in Table 3 and the corresponding calculated results
In one embodiment, it is noted that the whole step S2 is performed in order to obtain and store the relative pressure amplitude ppcvamptmp _ w. The subsequent diagnosis is also made for the relative pressure amplitude ppcvamptmp _ w, and in the subsequent step, due to the problem related to the cycle extraction, the initial phase of step S2 for obtaining the relative pressure amplitude ppcvamptmp _ w is executed when the current operating condition satisfies the diagnosis condition. That is, in the present embodiment, the relative pressure amplitude ppcvamptmp _ w may be calculated and stored if and only if the current operating condition satisfies the corresponding condition; however, since the pressure sensor 6 may always acquire the pressure value ppcv, the pressure value ppcv may always be acquired and the relative pressure amplitude ppcvmptmp _ w may be calculated and acquired, and the relative pressure amplitude ppcvmptmp _ w may be stored only when the current operating condition satisfies the diagnosis condition. It is to be understood that the above explanation of the process of the present invention is not limited to the specific embodiment of when the pressure value ppcv is acquired and the stored relative pressure amplitude ppcvmptmp _ w is calculated, as long as the relative pressure amplitude ppcvmptmp _ w is recorded within the valid time period.
And step S3: relative pressure amplitude processing is performed to obtain a relative pressure amplitude maximum value.
In one embodiment, in step S3: the step of performing relative pressure amplitude processing to obtain a maximum value of the relative pressure amplitude includes: when the current working condition does not meet the diagnosis condition, controlling a timer to stop timing; when the current working condition meets the diagnosis condition, controlling a timer to start timing; judging whether the accumulated time timed by the timer reaches a preset time length or not; if yes, all relative pressure amplitudes in the accumulated time timed by the timer are obtained to obtain the maximum value of the relative pressure amplitudes, and the timer is reset.
In one embodiment, when the vehicle operating condition satisfies the diagnosis condition, the relative pressure amplitude ppcvamptmp _ w is standardized uniformly, so that the two cases of the fault and the no fault can be distinguished obviously in the diagnosis process. That is, the current working condition is judged to be whether the current working condition meets the diagnosis condition, and if the current working condition meets the diagnosis condition, the timer is controlled to start timing; if not, the timing is not carried out or stopped. When the accumulated time counted by the timer reaches the preset time length, the preset time length may be preferably 5s, that is, it is determined whether the accumulated time length counted by the timer reaches 5s. It should be noted that, in the case that the determination condition is not satisfied, the timer does not count time, that is, the 5s counted up in the actual cumulative time is not necessarily continuous, or the current working condition is satisfied in the corresponding time of the timing. Then, if the accumulated timing duration reaches 5s, acquiring all relative pressure amplitudes ppcvamptmp _ w in the accumulated time timed by the timer, and counting the maximum value of the relative pressure amplitudes ppcvamptmp in the 5s crankcase ventilation pipe 3, namely the maximum value of the pressure amplitudes ppcvampds (1); if the timer fails to reach 5s, the pressure amplitude will not be processed. If the accumulated time duration reaches the preset time duration, the timer returns to zero again for timing, a period corresponding to the next preset time duration is waited, namely if the timer returns to zero again, the maximum value ppcvmps (n) of the pressure amplitude in the next 5s period is counted again. Wherein, likewise, all pressure amplitude maximum values ppcvmpds (n) are stored for extraction for uniform analysis during subsequent diagnostic procedures.
And step S4: all relative pressure amplitude maxima within one driving cycle are compared to diagnostic criteria.
In one embodiment, in step S4: in the step of comparing all the maximum values of the amplitude of the relative pressure within one driving cycle with diagnostic criteria, the diagnostic criteria comprising a fault threshold and a repair threshold: the step of comparing with a diagnostic standard comprises: if a maximum value of the relative pressure amplitude is smaller than the fault threshold value, the counting 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 no fault counter counts up by 1.
In one embodiment, after a driving cycle, i.e. after the vehicle completes the whole process of ignition, running and flameout, all pressure amplitude maximum values ppcvmps (n) in the whole process are extracted and analyzed. The main analysis process is to compare the maximum value of the pressure amplitude ppcvmps (n) with diagnostic criteria, wherein the diagnostic criteria include: a failure threshold and a repair threshold. Wherein for specific values of the failure threshold and the repair threshold, it may be preferable that the failure threshold is 4hPa; the repair threshold is 12hPa. Comparing the maximum value of the pressure amplitude ppcvmps (n) of a driving cycle with a fault threshold value and a repair threshold value, and if the maximum value of the pressure amplitude ppcvmps (n) is less than or equal to the fault threshold value 4hPa, adding 1 to the count of the fault counter; if a maximum pressure amplitude value ppcvampds (n) is greater than or equal to the repair threshold value 12hPa, the no-fault counter counts by 1. The specific values of the fault threshold and the repair threshold are the preferred results obtained through the test after the experiment of the method, and specifically refer to fig. 3a, where fig. 3a is a drop-point diagram of the test results of the amplitude method provided by the first embodiment of the present invention. It is seen that a large number of dots fall in the range of more than 12hPa, and a small number fall in the range of less than 4hPa, so that it is preferable to consider belonging to more than 12hPa as a normal state, whereas belonging to less than 4hPa as a fault state, and a diagnostic false alarm is presumed in the range of 4 to 12hPa. It is understood that the failure threshold value of 4hPa and the repair threshold value of 12hPa are preferable results obtained by experiments, and are not limited to the values exemplified in the present embodiment, and may be adjusted according to the vehicle.
Step S5: and diagnosing according to the comparison result and outputting a diagnosis result.
In one embodiment, in step S5: the step of diagnosing according to the comparison result and outputting the diagnosis result comprises the following steps: when the sum of the non-fault counter and the fault counter meets the counting threshold value, comparing the counting numerical values of the non-fault counter and the fault counter; when the value of the fault counter is larger than that of the fault-free counter, outputting a drop-out fault warning; and when the numerical value of the fault counter is smaller than that of the fault-free counter, outputting repair fault prompt information or fault-free prompt information.
In one embodiment, after step S4 is executed, since the non-failure counter and the failure counter have respective technologies, when the sum of the two only satisfies the counting threshold, wherein the technology threshold is preferably 5, that is, when the sum of the non-failure counter and the failure counter is equal to 5, the sizes of the non-failure counter and the failure counter are compared: if the fault counter is larger than the non-fault counter, outputting a drop fault warning, namely, a drop fault exists in the high-load pipeline (close to the crankcase end); if the fault counter is smaller than the non-fault counter, the fault repair prompt message or the non-fault prompt message is output. The specific output mode may include, but is not limited to, being a corresponding indicator light or informing a user or a service person of corresponding information through an output device such as a screen or a speaker in a mode not limited to graphics and text or voice. It is understood that the counting threshold and the output diagnosis result are all simple enumeration processes in the present embodiment, and are not limited to the technology, and may be changed according to the specific situation in actual implementation.
In one embodiment, compared with an energy value method, the method does not need to calibrate the model pressure of the crankcase ventilation system under different engine working conditions according to a test vehicle, reduces the influence of vehicle difference on calibration data, and distinguishes fault states and non-fault states according to a maximum value ppcvmps (n) of pressure amplitude obtained after processing of a pressure value ppcv measured by the PCV pressure sensor 6. The method can realize extremely low false alarm probability and high robustness. According to 3 sigma statistical analysis, the current fault threshold value of an energy value method adopted by a normal pipeline close to an empty filter end is 0.68, and the false alarm fault risk rate is 5 per thousand (the probability of more than 0.68 in normal distribution (mu =0.14, sigma = 0.21)); the amplitude method adopted by the invention is adopted at the normal pipeline close to the crankcase end, the fault threshold value is 4hpa at present, the false alarm fault risk is 1.3 permillage (the probability of less than 4hpa in normal distribution (mu =20.12, sigma = 5.36)), and the false alarm rate is reduced by nearly 3/4. Reference may be made in particular to fig. 3a to 4b. In general, the specific implementation flow of the crankcase ventilation pipeline falling-off diagnosis method provided by the first embodiment of the invention can refer to fig. 5, which is actually an extension of step S1 to step S5, and the specific details can refer to the descriptions of the corresponding steps in the foregoing, wherein the diagnosis conditions in step S2 are detailed in fig. 5, and the S4 diagnosis standard values include specific values of the fault threshold value and the repair threshold value, so that in fig. 5, which is a preferred case of the present embodiment, the values of the actual diagnosis conditions and the diagnosis standard values are not limited to the examples in the figure, and can be adjusted according to the actual situation.
The crankcase ventilation pipeline falling-off diagnosis method provided by the first embodiment of the invention comprises the following steps: step S1: acquiring the current working condition of the vehicle; step S2: when the current working condition meets the diagnosis condition, acquiring a pressure value in a crankcase ventilation pipe, and correspondingly acquiring a relative pressure amplitude according to the pressure value; and step S3: performing relative pressure amplitude processing to obtain a relative pressure amplitude maximum value; and step S4: comparing all relative pressure amplitude maxima within a driving cycle with diagnostic criteria; step S5: and diagnosing according to the comparison result and outputting a diagnosis result. Therefore, the invention can distinguish whether the pipeline falls off according to the pressure fluctuation in the ventilation pipe of the crankcase so as to meet the purpose of diagnosis. Compared with the prior art, the method greatly reduces the false alarm rate and improves the robustness. The method brings guiding significance for diagnosing the falling of the pipeline for installing the pressure sensor, greatly reduces the false alarm rate, reduces the time of calibration work and human resources, reduces the operation of a user, increases the convenience of the user, and improves the use experience of the user.
Second embodiment
Fig. 6 is a first structural schematic diagram of a crankcase ventilation pipeline falling-off diagnostic device according to a second embodiment of the invention. For a clear description of the crankcase ventilation line out-of-range diagnostic device 110 provided in accordance with the second embodiment of the present invention, please refer to fig. 1 and 6.
A crankcase ventilation line drop diagnostic device 110 according to a second embodiment of the present invention includes at least: a processor a101 and a memory a201, wherein the processor a101 is configured to execute a computer program A6 stored in the memory a201 to implement the steps of the crankcase ventilation pipeline falling-off diagnosis method as described in the first embodiment.
In one embodiment, the crankcase ventilation circuit falling off diagnostic device 110 provided by the present embodiment includes at least one processor a101 and at least one memory a201. Among them, at least one processor a101 may be referred to as a processing unit A1, and at least one memory a201 may be referred to as 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 falling-off diagnosis device 110 provided by the present embodiment is caused to implement the steps of the crankcase ventilation pipeline falling-off diagnosis method as described in the first embodiment. For example, step S1 shown in fig. 1: acquiring the current working condition of the vehicle; step S2: when the current working condition meets the diagnosis condition, acquiring a pressure value in a crankcase ventilation pipe, and correspondingly acquiring a relative pressure amplitude according to the pressure value; and step S3: performing relative pressure amplitude processing to obtain a relative pressure amplitude maximum value; and step S4: comparing all relative pressure amplitude maxima within a driving cycle with diagnostic criteria; step S5: and diagnosing according to the comparison result and outputting a diagnosis result.
In one embodiment, the crankcase ventilation pipeline falling off diagnostic device 110 provided in the present embodiment may include a plurality of storages a201 (simply referred to as storage units A2).
The storage unit A2 may be a volatile memory or a nonvolatile memory, or may include both volatile and nonvolatile memories. Among them, the nonvolatile Memory may be a Read Only Memory (ROM), a Programmable Read Only Memory (PROM), an Erasable Programmable Read-Only Memory (EPROM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a magnetic random access Memory (FRAM), a Flash Memory (Flash Memory), a magnetic surface Memory, an optical Disc, or a Compact Disc Read-Only Memory (CD-ROM); the magnetic surface storage may be disk storage or tape storage. Volatile Memory can be Random Access Memory (RAM), which acts as external cache Memory. By way of illustration and not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), synchronous Static Random Access Memory (SSRAM), dynamic Random Access Memory (DRAM), synchronous Dynamic Random Access Memory (SDRAM), double Data Rate Synchronous Dynamic Random Access Memory (DDRSDRAM), enhanced Synchronous Dynamic Random Access Memory (ESDRAM), enhanced Synchronous Dynamic Random Access Memory (Enhanced DRAM), synchronous Dynamic Random Access Memory (SLDRAM), direct Memory (DRmb Access), and Random Access Memory (DRAM). The memory unit A2 described in the embodiments of the present invention is intended to comprise, without being limited to, these and any other suitable types of memory.
In one embodiment, the storage unit A2 preferably stores a crankcase ventilation line falling off diagnostic method according to the first embodiment of the present invention. Further, it is also possible to temporarily store the value of the pressure value ppcv obtained by the pressure sensor 6, and the processor a101 correspondingly obtains a series of values such as the pressure sample difference value dppcv, the pressure wave peak value ppcvp, the pressure wave valley value ppcvv, the relative pressure amplitude ppcvmptmp _ w, and finally the maximum value of the pressure amplitude ppcvmpds (n) for diagnosis. When the processor a101 needs to perform calculation or read for diagnosis, the corresponding value stored in the previous execution step can be read from the storage unit A2.
In one embodiment, the crankcase ventilation circuit disengagement diagnostic device 110 may also include a bus connecting the various components (e.g., processor a101 and memory a201, output A3, etc.). The output device A3 can output a corresponding diagnosis result after completing the diagnosis, and the specific output device may include, but is not limited to, a display device displaying the diagnosis result to a user in a graphic mode; the voice broadcasting device displays the voice to the user in a voice playing mode; the system can also be an icon display device, corresponding icons, such as fault icons on a vehicle instrument panel, are displayed to prompt a user, and corresponding indicator lights can be obtained more simply, such as a red indicator light corresponding falling fault warning, a yellow corresponding repairing fault prompt message, a green corresponding non-fault prompt message and the like. The above output means may be one of the above examples, or may be any combination of two or more of them, and the examples are not particularly limited, and are only illustrative of the technique, as long as the result of diagnosis can be divided to the user.
In one embodiment, the crankcase ventilation line out-of-order diagnostic device 110 in this embodiment may further include a communication interface (e.g., I/O interface A4) that may be used to communicate with an external device. For example, as shown, the output device A3 is connected to the processor a101 via the I/O interface A4, as an intermediary for data transmission, a bridge, or the like.
In one embodiment, an I/O interface A4 may be connected to the vehicle can bus to obtain the current operating condition information of the vehicle, so that the processor a101 determines whether the operating condition of the vehicle satisfies the diagnostic condition for diagnosis.
In one embodiment, the crankcase ventilation pipeline falling off diagnostic device 110 provided by the present embodiment may further include a communication device A5. Specifically, the diagnostic result may be output for another terminal associated with the crankcase ventilation line drop diagnostic device 110 after the diagnosis is finished by the communication device A5. Specifically, the technologies employed in the communication connection include, but are not limited to, wireless and wired communication technologies. Still further, for wired Communication technologies, there may be included, but not limited to, ethernet (ETH), M-BUS, power Line Communication (PLC), 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 Mobile Communication (EDGE), wideband Code division multiple Access (W-CDMA), code Division Multiple Access (CDMA), time Division Multiple Access (TDMA), bluetooth, wireless Fidelity (WiFi) (e.g., IEEE802.11 a, IEEE802.11b, IEEE802.11g, and/or IEEE802.11 n), voice over internet protocol (VoIP), world Interoperability for Microwave Access (VoIP), and other suitable protocols for instant messaging, including any other suitable protocols, even those developed for short message Communication. In a specific embodiment, after the user turns off, the crankcase ventilation pipeline falling diagnosis device 110 performs diagnosis completion, and sends the diagnosis result to the mobile terminal of the user or the maintenance terminal of the maintenance personnel through the communication device A5, so that the user or the maintenance personnel can refer to the diagnosis result through the corresponding terminal, and the user or the maintenance personnel can not bother to obtain the diagnosis result through the crankcase ventilation pipeline falling diagnosis device 110 installed in the vehicle.
The crankcase ventilation pipeline falling-off diagnostic device 110 provided by the second embodiment of the invention comprises a memory a101 and a processor a201, and the processor a101 is used for executing the computer program A6 stored in the memory a201 to realize the steps of the crankcase ventilation pipeline falling-off diagnostic method described in the first embodiment, so that the crankcase ventilation pipeline falling-off diagnostic device 110 provided by the embodiment can distinguish whether the pipeline falls off according to the pressure fluctuation in the crankcase ventilation pipeline so as to meet the purpose of diagnosis. Compared with the prior art, the method greatly reduces the false alarm rate and improves the robustness. The method brings guiding significance for pipeline falling diagnosis of the pressure sensor, greatly reduces the false alarm rate, simultaneously reduces the calibration work time and human resources, reduces the operation of a user, increases the convenience of the user, and improves the use experience of the user.
The second embodiment of the present invention also provides a vehicle including the crankcase ventilation circuit disengagement diagnosis apparatus 110 according to the second embodiment of the present invention.
In one embodiment, the particular method of installation for the crankcase ventilation line pull-off diagnostic device 110 may include, but is not limited to, being a separate device in the vehicle; it may also be a unit in the PCV system, i.e. comprised in the PCV system; the vehicle-mounted terminal can also be a functional module in the vehicle-mounted terminal, and all the embodiments can be correspondingly executed by the vehicle-mounted terminal in the vehicle. It is to be understood that the above examples are illustrative of the technology and that the actual arrangement is not limited to the above examples.
The second embodiment of the present invention also provides a computer-readable storage medium storing a computer program A6, which when executed by the processor a101, implements the steps of the crankcase ventilation circuit disengagement diagnosis method as described in the first embodiment.
In an embodiment, the computer readable storage medium provided by the embodiment may include any entity or device capable of carrying computer program code, a recording medium, 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 in the foregoing, and are not described herein again.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, a reference to an element identified by the phrase "comprising one of 82308230a of 82303030, or an element defined by the phrase" comprising another identical element does not exclude the presence of the same element in a process, method, article, or apparatus comprising the element, and elements having the same designation may or may not have the same meaning in different embodiments of the application, the particular meaning being determined by its interpretation in the particular embodiment or by further reference to the context of the particular embodiment. As used herein, the meaning of "a plurality" or "a plurality" is two or more unless otherwise specified.
It should be understood that, although the steps in the flowcharts in the embodiments of the present application are shown in sequence as indicated by the arrows, the steps are not necessarily performed in sequence as indicated by the arrows. The steps are not performed in the exact order shown and may be performed in other orders unless explicitly stated herein. Moreover, at least some of the steps in the figures may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, in different orders, and may be performed alternately or partially with other steps or at least some of the sub-steps or stages of other steps.
It will be understood by those skilled in the art that all or part of the steps of implementing the above method embodiments may be implemented by hardware associated with program instructions, and the program may be stored in a computer readable storage medium, and when executed, performs the steps including the above method embodiments. The foregoing storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. A crankcase ventilation pipeline falling-off diagnosis method 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 a crankcase ventilation pipe, and correspondingly acquiring a relative pressure amplitude according to the pressure value;
performing relative pressure amplitude processing to obtain a relative pressure amplitude maximum value;
comparing all of said relative pressure amplitude maxima within a driving cycle to diagnostic criteria;
and diagnosing according to the comparison result and outputting a diagnosis result.
2. The crankcase ventilation line drop diagnostic method according to claim 1, wherein the step of obtaining the current operating condition of the vehicle comprises:
acquiring current temperature information, wherein the current temperature information comprises an ambient temperature, a current engine coolant temperature and delay time;
acquiring current engine working condition information, wherein the engine working condition information comprises an engine intake flow value, an engine intake 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 out diagnostic method of claim 2, said diagnostic condition comprising:
when the environment temperature is higher than a preset temperature threshold, and the delay time reaches a first time threshold; or when the environment temperature is lower than a preset temperature threshold, the engine coolant temperature reaches a corresponding coolant temperature threshold, and the corresponding delay time reaches a second time threshold;
the engine intake flow value is within a flow threshold range;
the engine intake air flow rate variation value is within a variation threshold range;
the rotating speed of the engine is within a preset rotating speed range;
the boost pressure is greater than a boost threshold;
the working information of the pressure sensor accords with the normal working condition.
4. The crankcase ventilation pipeline falling-off diagnosis method according to claim 1, wherein when the current working condition meets the diagnosis condition, the step of obtaining the diagnosis information comprises the following steps:
when the current working condition meets the diagnosis condition, acquiring the plurality of pressure values according to a preset frequency;
calculating the pressure sample difference value of two adjacent pressure values;
judging whether the pressure sample difference value is larger than 0:
if so, assigning a new pressure value in the two pressure values to the pressure wave peak value;
if not, assigning a new pressure value of the two pressure values to the pressure wave valley value;
and calculating the difference value between the current pressure wave peak value and the current wave valley value after each assignment to obtain the corresponding relative pressure amplitude, and storing the relative pressure amplitude.
5. The crankcase ventilation line drop diagnostic method of claim 1, wherein the step of performing relative pressure amplitude processing to obtain a maximum value of the relative pressure amplitude comprises:
when the current working condition does not meet the diagnosis condition, controlling a timer to stop timing;
when the current working condition meets the diagnosis condition, controlling a timer to start timing;
judging whether the accumulated time timed by the timer reaches a preset time length or not;
if yes, all the relative pressure amplitudes in the accumulated time timed by the timer are obtained to obtain the maximum value of the relative pressure amplitudes, and the timer is reset.
6. The crankcase ventilation circuit disengagement diagnostic method according to claim 1 wherein said step of comparing all of said maximum relative pressure amplitude values over a driving cycle to diagnostic criteria, said diagnostic criteria including fault thresholds and repair thresholds:
the step of comparing to a diagnostic standard comprises:
if one maximum value of the relative pressure amplitude is smaller than the fault threshold value, the count of the fault counter is increased by 1;
if there is one maximum value of the relative pressure amplitude that is greater than the repair threshold, then the no fault counter counts up by 1.
7. The crankcase ventilation pipeline falling-off diagnosis method according to claim 6, wherein the step of performing diagnosis based on the comparison result and outputting the diagnosis result comprises the steps of:
when the sum of the fault-free counter and the fault counter meets a counting threshold value, comparing the counting numerical values of the fault-free counter and the fault counter;
when the value of the fault counter is larger than that of the fault-free counter, outputting a drop-out fault warning;
and when the numerical value of the fault counter is smaller than that of the fault-free counter, outputting repair fault prompt information or fault-free prompt information.
8. The crankcase ventilation pipeline falling diagnosis device is characterized by comprising a processor and a memory:
the processor is configured to execute a computer program stored in the memory to implement the crankcase ventilation line out diagnostic method steps of any of claims 1-7.
9. A vehicle characterized by comprising the crankcase ventilation line drop diagnostic device of claim 8.
10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program which, when being executed by a processor, carries out the steps of the crankcase ventilation circuit disengagement diagnosis method according to any one of claims 1 to 7.
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