CN111852653B - Diagnostic device and diagnostic method for crankcase ventilation pipeline - Google Patents
Diagnostic device and diagnostic method for crankcase ventilation pipeline Download PDFInfo
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- CN111852653B CN111852653B CN201910335632.6A CN201910335632A CN111852653B CN 111852653 B CN111852653 B CN 111852653B CN 201910335632 A CN201910335632 A CN 201910335632A CN 111852653 B CN111852653 B CN 111852653B
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- 238000009423 ventilation Methods 0.000 title claims abstract description 167
- 238000002405 diagnostic procedure Methods 0.000 title description 15
- 238000000034 method Methods 0.000 claims description 13
- 238000010606 normalization Methods 0.000 claims description 8
- 230000007257 malfunction Effects 0.000 claims 2
- 238000003745 diagnosis Methods 0.000 abstract description 5
- 239000007789 gas Substances 0.000 description 30
- 230000001105 regulatory effect Effects 0.000 description 17
- 239000003921 oil Substances 0.000 description 10
- 230000008859 change Effects 0.000 description 9
- 238000002485 combustion reaction Methods 0.000 description 9
- 238000004140 cleaning Methods 0.000 description 7
- 230000010354 integration Effects 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 3
- 239000010687 lubricating oil Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000011010 flushing procedure Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B77/00—Component parts, details or accessories, not otherwise provided for
- F02B77/08—Safety, indicating, or supervising devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
- F01M13/00—Crankcase ventilating or breathing
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- General Engineering & Computer Science (AREA)
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- Combustion & Propulsion (AREA)
- Lubrication Details And Ventilation Of Internal Combustion Engines (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The invention relates to a diagnosis device for a crankcase ventilation pipelineThe diagnostic device comprises: the sensing unit is used for measuring the actual negative pressure energy P value in the high-load ventilation pipeline under each working condition; a central unit for calculating target negative pressure energy P in the high-load ventilation pipeline under each working conditionmodelThe value is calculated, and the actually measured negative pressure energy P value and the target negative pressure energy P are calculatedmodelDeviation between values; and the judging unit is used for judging the fault position of the high-load ventilation pipeline according to the deviation value. The invention constantly measures the negative bias in the high-load ventilation pipeline and measures the actually measured negative pressure energy P value and the target negative pressure energy PmodelAnd the deviation between the values is used as a fault judgment standard to judge whether the high-load ventilation pipeline has a damage fault and a fault position, so that the pollution gas in the ventilation pipeline is prevented from leaking into the atmosphere in time, and the negative pressure in the crankcase ventilation pipeline is recovered in time.
Description
Technical Field
The invention relates to the technical field of vehicles, in particular to a diagnosis device and a diagnosis method for a crankcase ventilation pipeline.
Background
When an automobile engine (such as an internal combustion engine) works, high-pressure unburned mixed gas in a combustion chamber of a cylinder leaks into a crankcase through a gap between a piston group and a cylinder sleeve to a greater or lesser extent, and blow-by gas is generated. The main components of blow-by gas in the crankcase include unburned mixture gas leaked from the combustion chamber and lubricating oil vapor formed at high temperature. The crankcase ventilation system is characterized in that a pipeline used for connecting a crankcase and an air inlet pipeline or an air inlet manifold of an engine is a crankcase ventilation pipeline, and crankcase waste gas is exhausted through the crankcase ventilation pipeline. In order to prevent the blow-by gas from leaking into the crankcase to the atmosphere and causing environmental pollution, crankcase ventilation systems for internal combustion engines are generally designed as closed systems in the prior art. Usually, the unburned gas mixture in the crankcase is re-introduced into the combustion chamber through the crankcase ventilation pipeline to participate in combustion and then is discharged.
However, most of existing crankcase ventilation pipelines are hollow rubber pipes or plastic pipelines, so the crankcase ventilation pipelines are easy to be damaged or broken, which leads to the ventilation pipelines being communicated with the atmosphere, and the polluted gas in the ventilation pipelines leaks into the atmosphere.
At present, a flow meter is arranged between an air filter and a supercharger of a ventilation pipeline to diagnose the fault of the ventilation pipeline of the crankcase, specifically, when the leakage fault occurs, the deviation between the air inflow calculated by parameters such as supercharging pressure and the like and the air inflow measured by the flow meter is utilized, and whether the disconnection fault occurs in the ventilation pipeline of the crankcase is diagnosed by calculating the deviation. However, this method requires an intake air flow sensor in the ventilation line, which is costly, and also requires a small air flow to the intake system when a leakage fault occurs due to a small negative pressure of the air in the air-filtered line, so that the calculated deviation is small, i.e., the degree of fault discrimination is not high.
Accordingly, there remains a need for improved apparatus and methods for diagnosing a crankcase ventilation circuit disconnection fault.
Disclosure of Invention
The invention aims to provide a diagnostic device and a diagnostic method for a crankcase ventilation pipeline, which are used for improving the conventional device and method for diagnosing the disconnection fault of the crankcase ventilation pipeline.
In order to solve the problems in the prior art, the present invention provides a diagnostic apparatus for a crankcase ventilation line, the crankcase being communicated with one end of a high-load ventilation line, the other end of the high-load ventilation line being communicated with an intake air line, the diagnostic apparatus comprising:
the sensing unit is used for measuring the actual negative pressure energy P value in the high-load ventilation pipeline under each working condition;
a central unit for calculating target negative pressure energy P in the high-load ventilation pipeline under each working conditionmodelThe value is calculated, and the actually measured negative pressure energy P value and the target negative pressure energy P are calculatedmodelValue ofDeviation therebetween;
and the judging unit is used for judging the fault position of the high-load ventilation pipeline according to the deviation value.
Optionally, in the diagnostic device for the crankcase ventilation pipeline, the central unit includes a squaring module, and the squaring module calculates a measured negative pressure energy P value and a target negative pressure energy PmodelThe way of deviation between the values is as follows:
squaring the measured negative pressure energy P value;
for the target negative pressure energy PmodelThe value is squared;
calculating the square of the measured negative pressure energy P value and the target negative pressure energy PmodelDeviation of the square of the value.
Optionally, in the diagnostic apparatus for the crankcase ventilation pipeline, the central unit further includes an integration module, and the integration module calculates a measured negative pressure energy P value and a target negative pressure energy PmodelThe way of deviation between the values is as follows:
integrating the square of the measured negative pressure energy P value;
for the target negative pressure energy PmodelThe square of the value is integrated;
calculating the integral of the square of the actually measured negative pressure energy P value and the target negative pressure energy PmodelDeviation of the integral of the square of the value.
Optionally, in the diagnostic apparatus for a crankcase ventilation pipeline, the central unit further includes a normalization module, and the normalization module calculates a measured negative pressure energy P value and a target negative pressure energy PmodelThe way of deviation between the values is as follows:
calculating the target negative pressure energy PmodelThe difference between the integral of the square of the value and the integral of the square of the measured negative pressure energy P value;
calculating the difference and the target negative pressure energy PmodelThe ratio of the integrals of the squares of the values.
Optionally, in the diagnostic apparatus for a crankcase ventilation pipeline, the determining unit determining the fault according to the ratio includes:
and when the ratio is greater than or equal to 0.9 and less than or equal to 1, judging that one end of the high-load ventilation pipeline close to the air inlet pipeline has a disconnection fault.
Optionally, in the diagnostic apparatus for a crankcase ventilation pipeline, the determining unit further includes the following steps:
and when the ratio is more than or equal to 0.7 and less than 0.9, judging that one end of the high-load ventilation pipeline close to the crankcase has a disconnection fault.
Optionally, in the diagnostic apparatus for a crankcase ventilation pipeline, the determining unit further includes the following steps:
and when the ratio is more than or equal to-0.2 and less than or equal to 0.2, judging that the high-load ventilation pipeline is normal.
The invention also provides a diagnostic method of the crankcase ventilation pipeline, wherein the crankcase is communicated with one end of a high-load ventilation pipeline, and the other end of the high-load ventilation pipeline is communicated with an air inlet pipeline, and the diagnostic method comprises the following steps:
measuring the actual negative pressure energy P value in the high-load ventilation pipeline under each working condition;
calculating the target negative pressure energy P in the high-load ventilation pipeline under each working conditionmodelThe value is calculated, and the actually measured negative pressure energy P value and the target negative pressure energy P are calculatedmodelDeviation between values;
and judging the fault position of the high-load ventilation pipeline according to the deviation value.
Optionally, in the diagnostic method for the crankcase ventilation pipeline, the measured negative pressure energy P value and the target negative pressure energy P are calculatedmodelThe deviation between the values comprises the following steps:
squaring the measured negative pressure energy P value;
for the target negative pressure energy PmodelThe value is squared;
calculating the square of the measured negative pressure energy P value and the target negative pressure energy PmodelDeviation of the square of the value.
Optionally, in the diagnostic method for the crankcase ventilation pipeline, the measured negative pressure energy P value and the target negative pressure energy P are calculatedmodelThe deviation between the values further comprises the steps of:
integrating the square of the measured negative pressure energy P value;
for the target negative pressure energy PmodelThe square of the value is integrated;
calculating the integral of the square of the actually measured negative pressure energy P value and the target negative pressure energy PmodelDeviation of the integral of the square of the value.
Optionally, in the diagnostic method for the crankcase ventilation pipeline, the measured negative pressure energy P value and the target negative pressure energy P are calculatedmodelThe deviation between the values further comprises the steps of:
calculating the target negative pressure energy PmodelThe difference between the integral of the square of the value and the integral of the square of the measured negative pressure energy P value;
calculating the difference and the target negative pressure energy PmodelThe ratio of the integrals of the squares of the values.
Optionally, in the diagnostic method for the crankcase ventilation pipeline, determining a fault according to the ratio includes the following steps:
and when the ratio is greater than or equal to 0.9 and less than or equal to 1, judging that one end of the high-load ventilation pipeline close to the air inlet pipeline has a disconnection fault.
Optionally, in the diagnostic method for the crankcase ventilation pipeline, determining the fault according to the ratio further includes:
and when the ratio is more than or equal to 0.7 and less than 0.9, judging that one end of the high-load ventilation pipeline close to the crankcase has a disconnection fault.
Optionally, in the diagnostic method for the crankcase ventilation pipeline, determining the fault according to the ratio further includes:
and when the ratio is more than or equal to-0.2 and less than or equal to 0.2, judging that the high-load ventilation pipeline is normal.
The crankcase ventilation pipeline provided by the inventionBy constantly measuring the negative bias in the high-load ventilation pipeline and by using the measured negative pressure energy P value and the target negative pressure energy PmodelAnd the deviation between the values is used as a fault judgment standard to judge whether the high-load ventilation pipeline has a damage fault and a fault position, so that the pollution gas in the ventilation pipeline is prevented from leaking into the atmosphere in time, and the negative pressure in the crankcase ventilation pipeline is recovered in time.
Drawings
FIG. 1 is a flow chart of a method of diagnosing a crankcase ventilation circuit according to an embodiment of the invention.
Fig. 2 is a graph showing the negative pressure characteristic and the negative pressure ratio when the high-load ventilation pipeline provided by the embodiment of the invention is normal.
Fig. 3 is a graph showing the negative pressure characteristic and the negative pressure ratio when the cleaning end of the high-load ventilation pipeline is disconnected according to the embodiment of the present invention.
Fig. 4 is a graph showing the negative pressure characteristic and the negative pressure ratio when the contaminated end of the high-load ventilation pipeline is disconnected according to the embodiment of the present invention.
Fig. 5a to 5b are schematic structural views of a crankcase ventilation pipeline according to an embodiment of the invention.
Wherein, 1-air filtration; 2-a supercharger; 3, an intercooler; 4-a throttle valve; 5-a first pressure regulating valve; 6-low load ventilation pipeline; 7-a first oil-gas separator; 8-a crankcase; 9-an intake air temperature sensor; 10-an intake pressure sensor; 11-an intake manifold; 12-a second oil-gas separator; 13-a second pressure regulating valve; 14-high load ventilation line; 15-a sensor; 16-an air intake line;
101-change curve of target negative pressure energy along with time; 102-the variation curve of the actually measured negative pressure energy along with the time; 103-deviation ratio of negative pressure energy along with time.
Detailed Description
The invention will be described in more detail below with reference to schematic drawings and examples. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
In the following, the terms "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances. Similarly, if the method described herein comprises a series of steps, the order in which these steps are presented herein is not necessarily the only order in which these steps may be performed, and some of the described steps may be omitted and/or some other steps not described herein may be added to the method.
The invention provides a diagnostic device of a crankcase ventilation pipeline, wherein the crankcase is communicated with one end of a high-load ventilation pipeline, and the other end of the high-load ventilation pipeline is communicated with an air inlet pipeline, and the diagnostic device comprises:
the sensing unit is used for measuring the actual negative pressure energy P value in the high-load ventilation pipeline under each working condition;
a central unit for calculating target negative pressure energy P in the high-load ventilation pipeline under each working conditionmodelThe value is calculated, and the actually measured negative pressure energy P value and the target negative pressure energy P are calculatedmodelDeviation between values;
and the judging unit is used for judging the fault position of the high-load ventilation pipeline according to the deviation value.
The invention constantly measures the negative bias in the high-load ventilation pipeline and measures the actually measured negative pressure energy P value and the target negative pressure energy PmodelAnd the deviation between the values is used as a fault judgment standard to judge whether the high-load ventilation pipeline has a damage fault and a fault position, so that the pollution gas in the ventilation pipeline is prevented from leaking into the atmosphere in time, and the negative pressure in the crankcase ventilation pipeline is recovered in time.
In one embodiment, the central unit comprises a squaring module that calculates a measured negative pressure energy P value and a target negative pressure energy PmodelThe way of deviation between the values is as follows:
squaring the measured negative pressure energy P value;
for the target negative pressure energy PmodelThe value is squared;
calculating the square of the measured negative pressure energy P value and the target negative pressure energy PmodelThe deviation of the square of the value is calculated as follows:
in one embodiment, the central unit further comprises an integration module, which calculates a measured negative pressure energy P value and a target negative pressure energy PmodelThe way of deviation between the values is as follows:
integrating the square of the measured negative pressure energy P value;
for the target negative pressure energy PmodelThe square of the value is integrated;
calculating the integral of the square of the actually measured negative pressure energy P value and the target negative pressure energy PmodelThe deviation of the integral of the square of the value is calculated as follows:
in one embodiment, the central unit further comprises a normalization module that calculates a measured negative pressure energy P value and a target negative pressure energy PmodelThe way of deviation between the values is as follows:
calculating the target negative pressure energy PmodelThe difference between the integral of the square of the value and the integral of the square of the measured negative pressure energy P value;
calculating the difference and the target negative pressure energy PmodelThe ratio of the integrals of the squares of the values is calculated as follows:
in the present embodiment, the determination method is shown in fig. 2-4, and fig. 2 is a graph of the negative pressure characteristic and the negative pressure ratio when the high-load ventilation pipeline is normal according to the embodiment of the present invention. Fig. 3 is a graph showing the negative pressure characteristic and the negative pressure ratio when the cleaning end of the high-load ventilation pipeline is disconnected according to the embodiment of the present invention. Fig. 4 is a graph showing the negative pressure characteristic and the negative pressure ratio when the contaminated end of the high-load ventilation pipeline is disconnected according to the embodiment of the present invention. The judging unit further comprises the following steps of:
when the ratio is greater than or equal to 0.9 and less than or equal to 1, judging that one end (namely a cleaning end) of the high-load ventilation pipeline close to the air inlet pipeline 16 generates disconnection fault;
when the ratio is more than or equal to 0.7 and less than 0.9, judging that one end (namely a polluted end) of the high-load ventilation pipeline close to the crankcase 8 generates disconnection fault;
otherwise, the high-load ventilation pipeline is judged to be normal, and the ratio value is usually within the range of more than or equal to-0.2 and less than or equal to 0.2 when the high-load ventilation pipeline is normal.
In one embodiment, as shown in fig. 5 a-5 b, fig. 5 a-5 b are schematic structural views of a crankcase ventilation circuit according to an embodiment of the invention. The crankcase ventilation conduit structure includes:
a crankcase 8, a high load vent line 14 and a low load vent line 6 communicating with said crankcase 8;
a sensor 15 disposed on the high-load vent line 14;
and an intake line 16 communicating with the high-load ventilation line 14, an intake manifold 11 communicating with the low-load ventilation line 6, the intake line 16 and the intake manifold 11 communicating through a throttle valve 4.
Further, the sensor 15 includes a pressure sensor or a flow sensor. The pressure sensor may be a relative pressure sensor or an absolute pressure sensor for measuring the negative bias pressure in the high-load vent line 14 and the flow sensor may be for measuring the flow of gas in the high-load vent line 14. In embodiments of the present invention, a pressure sensor, flow sensor or other sensor 15 that senses the gas in the high load vent line 14 may be used.
As shown in fig. 5a and 5b, the sensor 15 is disposed on the high-load ventilation pipeline 14, specifically, the sensor 15 may be disposed at any position in the high-load ventilation pipeline 14, for example, at the end of the high-load ventilation pipeline 14, i.e., at any one of the two ends, such as at the positions of (i) and (ii) in fig. 5 a; it may also be placed in the middle of the high-load ventilation line 14, as shown in fig. 5 b. Further, the end of the high-load ventilation line 14 close to the crankcase 8 is a contaminated end, as shown in fig. 5a at the position of (r); the end of the high load ventilation pipe 14 close to the air intake pipe 16 is a clean end, as shown in position (c) in fig. 5 a.
In the diagnostic device of the crankcase ventilation pipeline, a first oil-gas separator 7 is arranged at the interface of the crankcase 8 and the low-load ventilation pipeline 6, and a second oil-gas separator 12 is arranged at the interface of the crankcase 8 and the high-load ventilation pipeline 14. The first gas-oil separator 7 and the second gas-oil separator 12 are used for separating unburned mixed gas and lubricating oil vapor in blow-by gas, enabling the unburned mixed gas to enter the engine through the high-load ventilation pipeline 14 and the low-load ventilation pipeline 6 for re-combustion, and enabling the lubricating oil vapor to return to the crankcase 8 again. In addition, a first pressure regulating valve 5 is further arranged at the interface of the crankcase 8 and the low-load ventilation pipeline 6, a second pressure regulating valve 13 is further arranged at the interface of the crankcase 8 and the high-load ventilation pipeline 14, wherein the second pressure regulating valve 13 can be a passive solenoid valve or an active solenoid valve and is used for controlling the flushing flow of the crankcase 8.
Further, the first pressure regulating valve 5 is integrated into the first gas-oil separator 7, and the second pressure regulating valve 13 is integrated into the second gas-oil separator 12. Alternatively, the first pressure regulating valve 5 is located farther from the crankcase 8 than the first gas-oil separator 7, and the second pressure regulating valve 13 is located farther from the crankcase 8 than the second gas-oil separator 12.
In one embodiment, the first pressure regulating valve 5 and the second pressure regulating valve 13 are respectively arranged in the low load vent line 6 and the high load vent line 14, and the first pressure regulating valve 5 can be arranged next to the first gas-oil separator 7, as shown in fig. 5a for the arrangement of the first pressure regulating valve 5 and the first gas-oil separator 7 in the low load vent line. In another embodiment, the second pressure regulating valve 13 is integrated in the second gas-oil separator 12, as shown in fig. 5a in the manner of arranging the second pressure regulating valve 13 and the second gas-oil separator 12 in the high-load ventilation line. The main functions of the first pressure regulating valve 5 and the second pressure regulating valve 13 are to control the flushing flow of the crankcase 8 under different engine working conditions, and to avoid that the pressure in the air inlet pipeline 16 is too low and a large amount of unburned mixed gas in the crankcase 8 enters the engine in a low-load state, so as to control the engine to keep balance.
Further, one end of the air inlet pipeline 16 is connected with the air inlet manifold 11, and the other end is provided with an air filter 1; the air filter 1 is mainly used for purifying air. Further, the intake pipe 16 is further provided with a supercharger 2 and an intercooler 3, so that the components on the intake pipe 16 are the air filter 1, the high-load ventilation pipe 14, the supercharger 2, the intercooler 3, and a throttle valve 4 connected to the intake manifold 11 in sequence. Wherein the supercharger 2 is used to increase the pressure in the intake line 16 and the intercooler 3 is used to cool the incoming gas. The intake manifold 11 is further provided with a temperature sensor and a pressure sensor, so that the components on the intake manifold 11 are the throttle valve 4, the low-load ventilation pipeline 6, the intake temperature sensor 9 and the intake pressure sensor 10 in sequence, and the intake temperature sensor 9 and the intake pressure sensor 10 are used for detecting the temperature and the air pressure of gas entering the engine.
In the diagnostic device for the crankcase ventilation pipeline provided by the invention, the treatment of the prior mixed gas in the blow-by gas in the crankcase 8 is as follows: when the engine is under high load, unburned mixed gas in the crankcase 8 is discharged through a high-load ventilation pipeline 14, the gas is subjected to pressure and temperature regulation through an air inlet pipeline 16, and when the engine needs to combust the gas, the gas enters the air inlet manifold 11 through the throttle valve 4 and then enters the engine for combustion; when the engine is at low load, the unburnt gas mixture in the crankcase 8 is discharged through the low load ventilation pipe 6, directly enters the intake manifold 11 and then enters the engine for combustion.
The invention further provides a diagnostic method of a crankcase ventilation pipeline, as shown in fig. 1, fig. 1 is a flowchart of the diagnostic method of the crankcase ventilation pipeline provided by the embodiment of the invention. The diagnostic method comprises the following steps:
s1: measuring the actual negative pressure energy P value in the high-load ventilation pipeline under each working condition;
s2: calculating the target negative pressure energy P in the high-load ventilation pipeline under each working conditionmodelA value;
s3: calculating the actually measured negative pressure energy P value and the target negative pressure energy PmodelDeviation between values;
s4: and judging the fault position of the high-load ventilation pipeline according to the deviation value.
The invention constantly measures the negative bias in the high-load ventilation pipeline and measures the actually measured negative pressure energy P value and the target negative pressure energy PmodelAnd the deviation between the values is used as a fault judgment standard to judge whether the high-load ventilation pipeline has a damage fault and a fault position, so that the pollution gas in the ventilation pipeline is prevented from leaking into the atmosphere in time, and the negative pressure in the crankcase ventilation pipeline is recovered in time. The invention can diagnose the disconnection fault of the high-load ventilation pipeline and can also clearly determine the approximate position of the disconnection fault, such as the fault of a clean end or a polluted end of the high-load ventilation pipeline. The invention is realized by measuring the actual negative pressure energy P value and the target negative pressure energy PmodelThe deviation between the values is used as the standard for judging the fault, so that the discrimination between the fault and the non-fault is improved, and the diagnosis is more reliable.
In one embodiment, a measured negative pressure energy P value and a target negative pressure energy P are calculatedmodelThe deviation between the values may comprise the steps of:
squaring the measured negative pressure energy P value;
for the target negative pressure energy PmodelThe value is squared;
calculating the square of the measured negative pressure energy P value and the target negative pressure energy PmodelThe deviation of the square of the value is calculated as follows:
in one embodiment, a measured negative pressure energy P value and a target negative pressure energy P are calculatedmodelThe deviation between the values may comprise the steps of:
integrating the square of the measured negative pressure energy P value;
for the target negative pressure energy PmodelThe square of the value is integrated;
calculating the integral of the square of the actually measured negative pressure energy P value and the target negative pressure energy PmodelThe deviation of the integral of the square of the value is calculated as follows:
in one embodiment, the normalization process may include the following steps:
calculating the target negative pressure energy PmodelThe difference between the integral of the square of the value and the integral of the square of the measured negative pressure energy P value;
calculating the difference and the target negative pressure energy PmodelThe ratio of the integrals of the squares of the values is calculated as follows:
in this embodiment, the fault condition is determined according to the ratio:
s41: when the ratio is more than or equal to 0.9 and less than or equal to 1, judging that one end (namely a cleaning end) of the high-load ventilation pipeline close to the air inlet pipeline generates disconnection fault;
s42: when the ratio is more than or equal to 0.7 and less than 0.9, judging that one end (namely a polluted end) of the high-load ventilation pipeline close to the crankcase generates disconnection fault;
s43: otherwise, the high-load ventilation pipeline is judged to be normal, and the ratio value is usually within the range of more than or equal to-0.2 and less than or equal to 0.2 when the high-load ventilation pipeline is normal.
Specifically, under the working condition of large engine load, the air flow rate between the air filter and the supercharger is high, so that a certain negative pressure is formed in the air inlet pipeline between the air filter and the supercharger, and in general, the larger the engine load is, the larger the air flow rate is, and the larger the negative pressure is formed in the air inlet pipeline between the air filter and the supercharger. Because the clean end and the polluted end of the high-load ventilation pipeline are directly communicated with the air inlet pipeline between the air filter and the supercharger, certain negative pressure energy also exists in the high-load ventilation pipeline, and the negative pressure energy is basically equal to the negative pressure energy in the air inlet pipeline. Therefore, the greater the engine load, the greater the intake air flow rate, and the greater the negative pressure in the high load vent line. As the sensor is arranged on the high-load ventilation pipeline, the sensor can acquire the actually-measured negative pressure energy P value in the high-load ventilation pipeline in real time. In addition, a calculation model of the negative pressure energy in the high-load ventilation pipeline is established according to the negative pressure in the high-load ventilation pipeline under different load and rotating speed working conditions of the engine, and the target negative pressure energy P in the high-load ventilation pipeline can be calculated according to the current load and rotating speed of the engine through the calculation modelmodelThe value is obtained.
In the diagnosis and judgment, in order to improve the discrimination between the fault state and the non-fault state, firstly, the actual measurement negative pressure energy and the target negative pressure energy in the high-load ventilation pipeline are respectively squared, and because the larger the load of the engine is, the larger the target negative pressure energy in the high-load ventilation pipeline is, and when the cleaning end or/and the pollution end is disconnected, the larger the difference between the actual measurement negative pressure energy and the target negative pressure energy is, the integration is only carried out under the working condition of higher load of the engine, so as to improve the difference between the actual measurement negative pressure energy and the target negative pressure energy. When the fault judgment is carried out, the difference value between the integral of the target negative pressure energy square and the integral of the actually measured negative pressure energy square is calculated, then the difference value is compared with the integral of the target negative pressure energy square, the ratio of the difference value and the target negative pressure energy square is calculated, and the normalization is carried out.
The calculation formula of the energy deviation ratio is as follows:
if the high-load ventilation pipeline is normal, the difference value between the target negative pressure energy and the actually measured negative pressure energy is very small, the calculated energy deviation ratio delta is less than 0.7, and the energy deviation ratio delta is usually between-0.2 and + 0.2; as shown in fig. 2, the curves in the figure are a change curve 101 of the target negative pressure energy with time, a change curve 102 of the measured negative pressure energy with time, and a change curve 103 of the deviation ratio of the negative pressure energy with time. If the disconnection fault occurs at the cleaning end, under the working condition of high load in the engine, the target negative pressure energy in the high-load ventilation pipeline calculated according to the model is larger, at the moment, the high-load ventilation pipeline is directly communicated with the atmosphere, the actually measured negative pressure energy in the high-load ventilation pipeline measured by the sensor is almost 0, the difference between the actual measured negative pressure energy and the measured negative pressure energy is larger, the obtained ratio delta is about 0.9-1, and whether the disconnection fault occurs at the cleaning end of the high-load ventilation pipeline can be judged; as shown in fig. 3, the curves in the figure are a change curve 101 of the target negative pressure energy with time, a change curve 102 of the measured negative pressure energy with time, and a change curve 103 of the deviation ratio of the negative pressure energy with time. If the disconnection fault occurs at the polluted end, under the working condition of high load in the engine, the target negative pressure energy in the high-load ventilation pipeline calculated according to the model is larger, at the moment, because a distance is reserved between the polluted end of the high-load ventilation pipeline and the air inlet pipeline, the actually measured negative pressure energy is larger than 0 and smaller than the target negative pressure energy, and after the ratio delta of the energy deviation is calculated through a normalization algorithm, when the ratio delta is 0.7< delta <0.9, the disconnection fault occurs at the polluted end. As shown in fig. 4, the curves in the figure are a change curve 101 of the target negative pressure energy with time, a change curve 102 of the measured negative pressure energy with time, and a change curve 103 of the deviation ratio of the negative pressure energy with time.
In summary, in the diagnostic apparatus and the diagnostic method for the crankcase ventilation pipeline provided by the invention, the negative bias in the high-load ventilation pipeline is measured at any time, and the measured negative pressure energy P value and the target negative pressure energy P are obtainedmodelAnd the deviation between the values is used as a fault judgment standard to judge whether the high-load ventilation pipeline has a damage fault and a fault position, so that the pollution gas in the ventilation pipeline is prevented from leaking into the atmosphere in time, and the negative pressure in the crankcase ventilation pipeline is recovered in time.
The foregoing embodiments are merely illustrative of the principles of the invention and its efficacy, and are not to be construed as limiting the invention. Those skilled in the art can make various changes, substitutions and alterations to the disclosed embodiments and technical contents without departing from the spirit and scope of the present invention.
Claims (6)
1. A diagnostic device for a crankcase ventilation circuit, said crankcase being in communication with one end of a high load ventilation circuit, the other end of said high load ventilation circuit being in communication with an air intake circuit, said diagnostic device comprising:
the sensing unit is used for measuring the actual negative pressure energy P value in the high-load ventilation pipeline under each working condition;
a central unit for calculating target negative pressure energy P in the high-load ventilation pipeline under each working conditionmodelThe value is calculated, and the actually measured negative pressure energy P value and the target negative pressure energy P are calculatedmodelDeviation between values; the central unit comprises a square module, an integral module and a normalization module, and calculates the actually measured negative pressure energy P value and the target negative pressure energy PmodelThe way of deviation between the values is as follows: integrating the square of the measured negative pressure energy P value; for the target negative pressure energy PmodelSquare of the value is integratedDividing; calculating the integral of the square of the actually measured negative pressure energy P value and the target negative pressure energy PmodelDeviation of the integral of the square of the value; the normalization module calculates the actually measured negative pressure energy P value and the target negative pressure energy PmodelThe way of deviation between the values is as follows: calculating the target negative pressure energy PmodelThe difference between the integral of the square of the value and the integral of the square of the measured negative pressure energy P value; calculating the difference and the target negative pressure energy PmodelThe ratio of the integrals of the squares of the values;
the judging unit is used for judging the fault position of the high-load ventilation pipeline according to the deviation value; the judging unit further comprises the following steps of: and when the ratio is more than or equal to 0.7 and less than 0.9, judging that one end of the high-load ventilation pipeline close to the crankcase has a disconnection fault.
2. The diagnostic device of a crankcase ventilation circuit according to claim 1, wherein the judging unit judging the malfunction based on the ratio includes the steps of:
and when the ratio is greater than or equal to 0.9 and less than or equal to 1, judging that one end of the high-load ventilation pipeline close to the air inlet pipeline has a disconnection fault.
3. The diagnostic device of a crankcase ventilation circuit according to claim 1, wherein the judging unit judging the malfunction according to the ratio further comprises the steps of:
and when the ratio is more than or equal to-0.2 and less than or equal to 0.2, judging that the high-load ventilation pipeline is normal.
4. A method of diagnosing a crankcase ventilation circuit, the crankcase being in communication with one end of a high load ventilation circuit, the other end of the high load ventilation circuit being in communication with an air intake circuit, the method comprising the steps of:
measuring the actual negative pressure energy P value in the high-load ventilation pipeline under each working condition;
calculating the high load under each working conditionTarget negative pressure energy P in charge ventilation pipelinemodelThe value is calculated, and the actually measured negative pressure energy P value and the target negative pressure energy P are calculatedmodelDeviation between values; calculating the actually measured negative pressure energy P value and the target negative pressure energy PmodelThe deviation between the values further comprises the steps of: integrating the square of the measured negative pressure energy P value; for the target negative pressure energy PmodelThe square of the value is integrated; calculating the integral of the square of the actually measured negative pressure energy P value and the target negative pressure energy PmodelDeviation of the integral of the square of the value; calculating the actually measured negative pressure energy P value and the target negative pressure energy PmodelThe deviation between the values further comprises the steps of: calculating the target negative pressure energy PmodelThe difference between the integral of the square of the value and the integral of the square of the measured negative pressure energy P value; calculating the difference and the target negative pressure energy PmodelThe ratio of the integrals of the squares of the values;
judging the fault position of the high-load ventilation pipeline according to the deviation value; judging the fault according to the ratio comprises the following steps: and when the ratio is more than or equal to 0.7 and less than 0.9, judging that one end of the high-load ventilation pipeline close to the crankcase has a disconnection fault.
5. The method of diagnosing a crankcase ventilation circuit according to claim 4, wherein determining a fault based on the ratio comprises the steps of:
and when the ratio is greater than or equal to 0.9 and less than or equal to 1, judging that one end of the high-load ventilation pipeline close to the air inlet pipeline has a disconnection fault.
6. The method of diagnosing a crankcase ventilation circuit according to claim 5, wherein determining a fault based on the ratio further comprises the steps of:
and when the ratio is more than or equal to-0.2 and less than or equal to 0.2, judging that the high-load ventilation pipeline is normal.
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| CN105484869A (en) * | 2014-10-03 | 2016-04-13 | 福特环球技术公司 | Crankcase integrity breach detection |
| CN105593480A (en) * | 2013-12-10 | 2016-05-18 | 宝马股份公司 | Method for detecting a leak in a crankcase breather |
| CN107532544A (en) * | 2015-07-24 | 2018-01-02 | 宝马股份公司 | Internal combustion engine and the method for the leakage for identifying crankcase ventilation system and/or fuel tank vent system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US9416694B2 (en) * | 2012-09-14 | 2016-08-16 | Ford Global Technologies, Llc | Crankcase integrity breach detection |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105593480A (en) * | 2013-12-10 | 2016-05-18 | 宝马股份公司 | Method for detecting a leak in a crankcase breather |
| CN105484869A (en) * | 2014-10-03 | 2016-04-13 | 福特环球技术公司 | Crankcase integrity breach detection |
| CN107532544A (en) * | 2015-07-24 | 2018-01-02 | 宝马股份公司 | Internal combustion engine and the method for the leakage for identifying crankcase ventilation system and/or fuel tank vent system |
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