CN111765003A - Engine crankcase ventilation device OBD diagnosis method based on electric loop - Google Patents
Engine crankcase ventilation device OBD diagnosis method based on electric loop Download PDFInfo
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- CN111765003A CN111765003A CN202010708438.0A CN202010708438A CN111765003A CN 111765003 A CN111765003 A CN 111765003A CN 202010708438 A CN202010708438 A CN 202010708438A CN 111765003 A CN111765003 A CN 111765003A
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- 238000003745 diagnosis Methods 0.000 title claims abstract description 131
- 238000009423 ventilation Methods 0.000 title claims abstract description 67
- 238000000034 method Methods 0.000 title claims description 14
- 238000001514 detection method Methods 0.000 claims abstract description 19
- 238000002405 diagnostic procedure Methods 0.000 claims abstract description 16
- 230000000007 visual effect Effects 0.000 claims abstract description 15
- 230000001960 triggered effect Effects 0.000 claims description 17
- 230000004913 activation Effects 0.000 claims description 8
- 238000010586 diagram Methods 0.000 description 5
- 239000000356 contaminant Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 231100000719 pollutant Toxicity 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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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W50/00—Details of control systems for road vehicle drive control not related to the control of a particular sub-unit, e.g. process diagnostic or vehicle driver interfaces
- B60W50/02—Ensuring safety in case of control system failures, e.g. by diagnosing, circumventing or fixing failures
- B60W50/0205—Diagnosing or detecting failures; Failure detection models
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W50/00—Details of control systems for road vehicle drive control not related to the control of a particular sub-unit, e.g. process diagnostic or vehicle driver interfaces
- B60W50/08—Interaction between the driver and the control system
- B60W50/14—Means for informing the driver, warning the driver or prompting a driver intervention
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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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/54—Testing for continuity
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- Automation & Control Theory (AREA)
- General Engineering & Computer Science (AREA)
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- Transportation (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
An electrical circuit based engine crankcase ventilation (OBD) diagnostic method based on a crankcase ventilation detection circuit comprising: the device comprises a ventilation pipe and an engine controller 4, wherein two ends of the ventilation pipe are respectively in press fit with switch contacts of a first contact switch and a second contact switch, one end of the first contact switch is connected with a PCV resistor and an ECU resistor in series in sequence and then is connected with a 5V direct current power supply in the engine controller, the other end of the first contact switch is connected with the second contact switch in series and then is connected with an ECU ground in the engine controller, and a PVC voltage detection point connected with an engine controller signal acquisition point is arranged between the PCV resistor and the ECU resistor; the diagnostic method comprises a first step of: diagnosis enabled, second step: high voltage diagnostics and low voltage diagnostics. The design not only has the function of diagnosis enabling, and the judgment logic is rigorous and reliable, but also adopts a visual warning system to prompt a driver and find faults in time.
Description
Technical Field
The invention relates to an OBD (on-board diagnostics) diagnosis method for an engine crankcase ventilation device based on an electric circuit, which is particularly suitable for strict judgment logic and realizes visual warning.
Background
According to the requirements of the emission standard of the sixth stage of China, a crankcase ventilation device of an automobile engine basically has to adopt a closed structure, and the crankcase ventilation device does not allow pollutants to be directly discharged into the atmosphere. In order to meet the requirements of the legislation, crankcase contaminants are usually led from the cylinder head cover to the intake pipe via a ventilation duct, where they are re-introduced into the cylinder for combustion. With this configuration, the ECU must have a corresponding OBD diagnostic strategy to ensure that when the crankcase ventilation duct is disconnected, causing direct discharge of crankcase contaminants into the atmosphere, the ECU diagnoses the disconnection fault in time and prompts the driver with a visual warning system.
Disclosure of Invention
The invention aims to solve the problems of non-strict judgment logic and non-visual warning system in the prior art, and provides an OBD (on-board diagnostics) diagnosis method for an engine crankcase ventilation device, which has strict judgment logic and is provided with a visual warning system based on an electric circuit.
In order to achieve the above purpose, the technical solution of the invention is as follows:
an engine crankcase ventilation (OBD) diagnostic method based on an electrical circuit, the engine crankcase ventilation (OBD) diagnostic method based on a crankcase ventilation detection circuit, the detection circuit comprising: the device comprises a ventilation pipe, a first contact switch, a second contact switch and an engine controller, wherein two ends of the ventilation pipe are respectively in press fit with switch contacts of the first contact switch and the second contact switch, one end of the first contact switch is connected with a PCV resistor and an ECU resistor in series in sequence and then is connected with a 5V direct current power supply in the engine controller, the other end of the first contact switch is connected with the second contact switch in series and then is connected with an ECU ground in the engine controller, and a PVC voltage detection point connected with a signal acquisition point of the engine controller is arranged between the PCV resistor and the ECU resistor 6;
the OBD diagnosis method for the engine crankcase ventilation device comprises the following steps:
the first step is as follows: the diagnosis enables, and engine controller gathers ignition key opening time signal, engine operation time signal, engine operating condition signal and storage battery voltage signal in real time, and engine controller judges whether satisfies the enabling condition:
the first condition is as follows: the ignition key on time is greater than a set ignition key on time threshold;
and a second condition: the engine running time is greater than or equal to a set engine running time threshold;
and (3) carrying out a third condition: the engine is not in a starting state;
and a fourth condition: the battery voltage is greater than a set battery voltage minimum threshold;
and a fifth condition: the battery voltage is less than the set maximum threshold value of the battery voltage;
when all of the above 5 conditions are satisfied, then both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are yes, i.e., high level; when any one of the above 5 conditions is not satisfied, both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are non, i.e., low level;
the second step is that: the method comprises the steps of high-voltage diagnosis and low-voltage diagnosis, wherein an engine controller collects PCV loop voltage diagnosis enabling state signals and PCV loop voltage diagnosis enabling condition state signals in real time, and collects PCV loop voltage at a PVC voltage detection point in real time;
high-pressure diagnosis: when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both yes, the engine controller continuously compares the magnitude relation between the PCV circuit voltage and a PCV circuit voltage high threshold, when the PCV circuit voltage is greater than or equal to the PCV circuit voltage high threshold, a PCV circuit voltage high event is triggered, the PCV circuit voltage high event is triggered to be set to be TRUE, the engine controller starts to record the duration of PCV circuit voltage high fault pending, when the recorded PCV circuit voltage high fault pending duration exceeds a set threshold, the PCV circuit voltage high fault _ is confirmed to be TRUE, the engine controller confirms fault activation, and a visual warning system prompts a driver to have a fault of PCV disconnection;
when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both not, assigning the value of the PCV circuit voltage diagnosis enabling state to the PCV circuit voltage high diagnosis enabling state, and assigning the value of the PCV circuit voltage diagnosis enabling condition state to the PCV circuit voltage high diagnosis enabling condition state, wherein the PCV circuit voltage high diagnosis enabling state and the PCV circuit voltage high diagnosis enabling condition state are both not, and after the PCV circuit voltage high diagnosis enabling state and the PCV circuit voltage high diagnosis enabling condition state are subjected to NOT logic, the duration time of the PCV circuit voltage high event is set to be zero and frozen, and the PCV open fault is not activated;
low-voltage diagnosis: when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both yes, the engine controller continuously compares the magnitude relation between the PCV circuit voltage and the PCV circuit voltage low threshold, when the PCV circuit voltage is smaller than or equal to the PCV circuit voltage low threshold, a PCV circuit voltage low event is triggered, the PCV circuit voltage low event is set to TRUE, the engine controller starts to record the duration time of PCV circuit voltage low fault pending, when the recorded duration time of PCV circuit voltage low fault pending exceeds the set threshold, the PCV circuit voltage low fault is confirmed to TRUE, the engine controller confirms fault activation, and a visual warning system prompts a driver that the fault of PCV ground short circuit occurs;
when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both not, the value of the PCV circuit voltage diagnosis enabling state is assigned to the PCV circuit voltage low diagnosis enabling state, and meanwhile, the value of the PCV circuit voltage diagnosis enabling condition state is assigned to the PCV circuit voltage low diagnosis enabling condition state, at the moment, the PCV circuit voltage low diagnosis enabling state and the PCV circuit voltage low diagnosis enabling condition state are both not, after the PCV circuit voltage low diagnosis enabling state and the PCV circuit voltage low diagnosis enabling condition state pass through NOT logic, the duration time of a PCV circuit voltage low event is set to be zero and frozen, and then the fault of PCV ground short circuit cannot be activated.
Connecting wires of the first contact switch and the second contact switch are embedded outside the ventilation pipe, the first contact switch and the second contact switch are both in a closed state when the ventilation pipe is normally installed, the second contact switch 3 is disconnected when the left end of the ventilation pipe falls off, and the first contact switch is disconnected when the right end of the ventilation pipe falls off.
The ignition key opening time points the time when the ignition key is placed in the ON gear.
The engine running time refers to the duration of the engine starting from a stop state and after the engine passes a starting state and the engine speed is greater than a calibrated threshold value of the running state.
The working state of the engine is judged according to the position of an ignition key and the rotating speed of the engine and is divided into four states of stopping, starting, running and flameout.
The ignition key opening time threshold, the engine running time threshold, the battery voltage minimum threshold and the battery voltage maximum threshold are set values and can be changed according to different vehicle types.
The PCV loop voltage high threshold and the PCV loop voltage low threshold are set voltage values and can be changed according to different vehicle types.
The set threshold value of the PCV loop voltage high fault pending duration is an artificial set value and can be changed according to different vehicle types;
the set threshold value of the PCV loop voltage low fault pending duration is an artificial set value and can be changed according to different vehicle types.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention relates to an engine controller in an OBD (on-board diagnostics) diagnosis method for an engine crankcase ventilation device based on an electric circuit, which is used for judging whether to start PCV (positive crankcase ventilation) circuit diagnosis according to vehicle conditions, if the diagnosis conditions are met, starting PCV electric circuit high diagnosis and PCV electric circuit low diagnosis, judging whether the PCV of the engine crankcase ventilation device is disconnected or not and judging whether the PCV of the engine crankcase ventilation device is short-circuited to the ground. Therefore, the design has a diagnosis enabling function and strict and reliable judgment logic.
2. According to the engine crankcase ventilation device OBD diagnosis method based on the electric circuit, event duration events are timely carried out after a PCV circuit voltage high event is triggered and a PCV circuit voltage low event is triggered, PCV faults are confirmed when the duration time exceeds the set time, and the accuracy of fault judgment is effectively improved. Therefore, the design has high fault judgment accuracy and effectively avoids fault false triggering.
3. According to the engine crankcase ventilation device OBD diagnosis method based on the electric loop, when the system confirms that the fault occurs, the visual warning system is adopted to prompt a driver, so that the fault is fed back to the driver in time, the driver is prompted to maintain in time, and the influence on driving safety due to the fact that the fault is not found in time is avoided. Therefore, the design adopts a visual warning system to prompt a driver, and the influence on driving safety due to untimely fault finding is avoided.
Drawings
Fig. 1 is a schematic structural view of the present invention.
FIG. 2 is a characteristic diagram of the feedback voltage of the PCV electrical loop of the present invention.
FIG. 3 is a schematic diagram of a PCV electrical circuit diagnostic overall strategy of the present invention.
Fig. 4 is a diagram of the PCV electrical circuit diagnostic enable determination strategy of fig. 3.
Fig. 5 is a schematic diagram of the PCV electrical circuit high diagnostic strategy of fig. 3.
Fig. 6 is a diagram of the PCV electrical circuit low diagnostic strategy of fig. 3.
In the figure: the device comprises a ventilation pipe 1, a first contact switch 2, a second contact switch 3, an engine controller 4, a PCV resistor 5, an ECU resistor 6 and a PVC voltage detection point 7.
Detailed Description
The present invention will be described in further detail with reference to the following description and embodiments in conjunction with the accompanying drawings.
Referring to fig. 1-6, an engine crankcase ventilation OBD diagnostic method based on an electrical circuit, the engine crankcase ventilation OBD diagnostic method based on a crankcase ventilation detection circuit, the detection circuit comprising: the device comprises a ventilation pipe 1, a first contact switch 2, a second contact switch 3 and an engine controller 4, wherein two ends of the ventilation pipe 1 are respectively in press fit with switch contacts of the first contact switch 2 and the second contact switch 3, one end of the first contact switch 2 is connected with a PCV (voltage controlled rectifier) resistor 5 and an ECU (electronic control unit) resistor 6 in series in sequence and then is connected with a 5-volt direct-current power supply in the engine controller 4, the other end of the first contact switch 2 is connected with the second contact switch 3 in series and then is connected with an ECU (electronic control unit) in the engine controller 4, and a PVC voltage detection point 7 connected with a signal acquisition point of the engine controller 4 is arranged between the PCV (voltage controlled rectifier) resistor 5 and the ECU;
the OBD diagnosis method for the engine crankcase ventilation device comprises the following steps:
the first step is as follows: the diagnosis enables, and engine controller 4 gathers ignition key opening time signal, engine operation time signal, engine operating condition signal and storage battery voltage signal in real time, and engine controller 4 judges whether satisfies the enabling condition:
the first condition is as follows: the ignition key on time is greater than a set ignition key on time threshold;
and a second condition: the engine running time is greater than or equal to a set engine running time threshold;
and (3) carrying out a third condition: the engine is not in a starting state;
and a fourth condition: the battery voltage is greater than a set battery voltage minimum threshold;
and a fifth condition: the battery voltage is less than the set maximum threshold value of the battery voltage;
when all of the above 5 conditions are satisfied, then both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are yes, i.e., high level; when any one of the above 5 conditions is not satisfied, both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are non, i.e., low level;
the second step is that: the engine controller 4 collects a PCV loop voltage diagnosis enabling state signal and a PCV loop voltage diagnosis enabling condition state signal in real time, and collects PCV loop voltage at a PVC voltage detection point 7 in real time;
high-pressure diagnosis: when both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are yes, the engine controller 4 continuously compares the magnitude relationship between the PCV circuit voltage and the PCV circuit voltage high threshold, when the PCV circuit voltage is greater than or equal to the PCV circuit voltage high threshold, a PCV circuit voltage high event is triggered, the PCV circuit voltage high event is triggered to be set to TRUE, the engine controller 4 starts to record the duration of PCV circuit voltage high fault _ pending, and when the recorded PCV circuit voltage high fault _ pending duration exceeds the set threshold, the PCV circuit voltage high fault _ confirmed to be set to TRUE, the engine controller 4 confirms fault activation, and a visual warning system prompts a driver that a PCV open fault occurs;
when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both not, assigning the value of the PCV circuit voltage diagnosis enabling state to the PCV circuit voltage high diagnosis enabling state, and assigning the value of the PCV circuit voltage diagnosis enabling condition state to the PCV circuit voltage high diagnosis enabling condition state, wherein the PCV circuit voltage high diagnosis enabling state and the PCV circuit voltage high diagnosis enabling condition state are both not, and after the PCV circuit voltage high diagnosis enabling state and the PCV circuit voltage high diagnosis enabling condition state are subjected to NOT logic, the duration time of the PCV circuit voltage high event is set to be zero and frozen, and the PCV open fault is not activated;
low-voltage diagnosis: when both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are yes, the engine controller 4 continuously compares the magnitude relationship between the PCV circuit voltage and the PCV circuit voltage low threshold, when the PCV circuit voltage is less than or equal to the PCV circuit voltage low threshold, a PCV circuit voltage low event is triggered, the PCV circuit voltage low event is triggered to be TRUE, the engine controller 4 starts to record the duration of PCV circuit voltage low fault _ pending, and when the recorded PCV circuit voltage low fault _ pending duration exceeds the set threshold, the PCV circuit voltage low fault _ confirmed to be TRUE, the engine controller 4 confirms fault activation, and prompts a driver to have a PCV ground short circuit fault through a visual warning system;
when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both not, the value of the PCV circuit voltage diagnosis enabling state is assigned to the PCV circuit voltage low diagnosis enabling state, and meanwhile, the value of the PCV circuit voltage diagnosis enabling condition state is assigned to the PCV circuit voltage low diagnosis enabling condition state, at the moment, the PCV circuit voltage low diagnosis enabling state and the PCV circuit voltage low diagnosis enabling condition state are both not, after the PCV circuit voltage low diagnosis enabling state and the PCV circuit voltage low diagnosis enabling condition state pass through NOT logic, the duration time of a PCV circuit voltage low event is set to be zero and frozen, and then the fault of PCV ground short circuit cannot be activated.
Connecting wires of the first contact switch 2 and the second contact switch 3 are embedded outside the ventilation pipe 1, the first contact switch 2 and the second contact switch 3 are both in a closed state when the ventilation pipe 1 is normally installed, the second contact switch 3 is disconnected when the left end of the ventilation pipe 1 falls off, and the first contact switch 2 is disconnected when the right end of the ventilation pipe 1 falls off.
The ignition key opening time points the time when the ignition key is placed in the ON gear.
The engine running time refers to the duration of the engine starting from a stop state and after the engine passes a starting state and the engine speed is greater than a calibrated threshold value of the running state.
The working state of the engine is judged according to the position of an ignition key and the rotating speed of the engine and is divided into four states of stopping, starting, running and flameout.
The ignition key opening time threshold, the engine running time threshold, the battery voltage minimum threshold and the battery voltage maximum threshold are set values and can be changed according to different vehicle types.
The PCV loop voltage high threshold and the PCV loop voltage low threshold are set voltage values and can be changed according to different vehicle types.
The set threshold value of the PCV loop voltage high fault pending duration is an artificial set value and can be changed according to different vehicle types;
the set threshold value of the PCV loop voltage low fault pending duration is an artificial set value and can be changed according to different vehicle types.
The principle of the invention is illustrated as follows:
assignment refers to assigning the former value to the latter, the former being 0 and the latter also being assigned 0, the former being 1 and the latter also being assigned 1.
The PCV is an engine crankcase ventilation device.
Example 1:
an engine crankcase ventilation (OBD) diagnostic method based on an electrical circuit, the engine crankcase ventilation (OBD) diagnostic method based on a crankcase ventilation detection circuit, the detection circuit comprising: the device comprises a ventilation pipe 1, a first contact switch 2, a second contact switch 3 and an engine controller 4, wherein two ends of the ventilation pipe 1 are respectively in press fit with switch contacts of the first contact switch 2 and the second contact switch 3, one end of the first contact switch 2 is connected with a PCV (voltage controlled rectifier) resistor 5 and an ECU (electronic control unit) resistor 6 in series in sequence and then is connected with a 5-volt direct-current power supply in the engine controller 4, the other end of the first contact switch 2 is connected with the second contact switch 3 in series and then is connected with an ECU (electronic control unit) in the engine controller 4, and a PVC voltage detection point 7 connected with a signal acquisition point of the engine controller 4 is arranged between the PCV (voltage controlled rectifier) resistor 5 and the ECU;
the OBD diagnosis method for the engine crankcase ventilation device comprises the following steps:
the first step is as follows: the diagnosis enables, and engine controller 4 gathers ignition key opening time signal, engine operation time signal, engine operating condition signal and storage battery voltage signal in real time, and engine controller 4 judges whether satisfies the enabling condition:
the first condition is as follows: the ignition key on time is greater than a set ignition key on time threshold;
and a second condition: the engine running time is greater than or equal to a set engine running time threshold;
and (3) carrying out a third condition: the engine is not in a starting state;
and a fourth condition: the battery voltage is greater than a set battery voltage minimum threshold;
and a fifth condition: the battery voltage is less than the set maximum threshold value of the battery voltage;
when all of the above 5 conditions are satisfied, then both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are yes, i.e., high level; when any one of the above 5 conditions is not satisfied, both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are non, i.e., low level;
the second step is that: the engine controller 4 collects a PCV loop voltage diagnosis enabling state signal and a PCV loop voltage diagnosis enabling condition state signal in real time, and collects PCV loop voltage at a PVC voltage detection point 7 in real time;
high-pressure diagnosis: when both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are yes, the engine controller 4 continuously compares the magnitude relationship between the PCV circuit voltage and the PCV circuit voltage high threshold, when the PCV circuit voltage is greater than or equal to the PCV circuit voltage high threshold, a PCV circuit voltage high event is triggered, the PCV circuit voltage high event is triggered to be set to TRUE, the engine controller 4 starts to record the duration of PCV circuit voltage high fault _ pending, and when the recorded PCV circuit voltage high fault _ pending duration exceeds the set threshold, the PCV circuit voltage high fault _ confirmed to be set to TRUE, the engine controller 4 confirms fault activation, and a visual warning system prompts a driver that a PCV open fault occurs;
when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both not, assigning the value of the PCV circuit voltage diagnosis enabling state to the PCV circuit voltage high diagnosis enabling state, and assigning the value of the PCV circuit voltage diagnosis enabling condition state to the PCV circuit voltage high diagnosis enabling condition state, wherein the PCV circuit voltage high diagnosis enabling state and the PCV circuit voltage high diagnosis enabling condition state are both not, and after the PCV circuit voltage high diagnosis enabling state and the PCV circuit voltage high diagnosis enabling condition state are subjected to NOT logic, the duration time of the PCV circuit voltage high event is set to be zero and frozen, and the PCV open fault is not activated;
low-voltage diagnosis: when both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are yes, the engine controller 4 continuously compares the magnitude relationship between the PCV circuit voltage and the PCV circuit voltage low threshold, when the PCV circuit voltage is less than or equal to the PCV circuit voltage low threshold, a PCV circuit voltage low event is triggered, the PCV circuit voltage low event is triggered to be TRUE, the engine controller 4 starts to record the duration of PCV circuit voltage low fault _ pending, and when the recorded PCV circuit voltage low fault _ pending duration exceeds the set threshold, the PCV circuit voltage low fault _ confirmed to be TRUE, the engine controller 4 confirms fault activation, and prompts a driver to have a PCV ground short circuit fault through a visual warning system;
when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both not, the value of the PCV circuit voltage diagnosis enabling state is assigned to the PCV circuit voltage low diagnosis enabling state, and meanwhile, the value of the PCV circuit voltage diagnosis enabling condition state is assigned to the PCV circuit voltage low diagnosis enabling condition state, at the moment, the PCV circuit voltage low diagnosis enabling state and the PCV circuit voltage low diagnosis enabling condition state are both not, after the PCV circuit voltage low diagnosis enabling state and the PCV circuit voltage low diagnosis enabling condition state pass through NOT logic, the duration time of a PCV circuit voltage low event is set to be zero and frozen, and then the fault of PCV ground short circuit cannot be activated.
Example 2:
example 2 is substantially the same as example 1 except that:
connecting wires of the first contact switch 2 and the second contact switch 3 are embedded outside the ventilation pipe 1, the first contact switch 2 and the second contact switch 3 are both in a closed state when the ventilation pipe 1 is normally installed, the second contact switch 3 is disconnected when the left end of the ventilation pipe 1 falls off, and the first contact switch 2 is disconnected when the right end of the ventilation pipe 1 falls off.
Example 3:
example 3 is substantially the same as example 2 except that:
the ignition key opening time points the time of the ignition key in an ON gear; the engine running time refers to the duration of the engine after the engine starts from a stop state and passes through a starting state, and the engine rotating speed is greater than a calibration threshold value of the running state; the working state of the engine is judged according to the position of an ignition key and the rotating speed of the engine and is divided into four states of stopping, starting, running and flameout; the ignition key opening time threshold, the engine running time threshold, the battery voltage minimum threshold and the battery voltage maximum threshold are set values and can be changed according to different vehicle types; the PCV loop voltage high threshold and the PCV loop voltage low threshold are set voltage values and can be changed according to different vehicle types; the set threshold value of the PCV loop voltage high fault pending duration is an artificial set value and can be changed according to different vehicle types; the set threshold value of the PCV loop voltage low fault pending duration is an artificial set value and can be changed according to different vehicle types.
Claims (8)
1. An engine crankcase ventilation device OBD diagnosis method based on an electric loop is characterized in that:
the engine crankcase ventilation OBD diagnostic method is based on a crankcase ventilation detection circuit, the detection circuit comprising: the device comprises a ventilation pipe (1), a first contact switch (2), a second contact switch (3) and an engine controller (4), wherein two ends of the ventilation pipe (1) are respectively in press fit with switch contacts of the first contact switch (2) and the second contact switch (3), one end of the first contact switch (2) is sequentially connected with a PCV resistor (5) and an ECU resistor (6) in series and then is connected with a 5-volt direct-current power supply in the engine controller (4), the other end of the first contact switch (2) is connected with the second contact switch (3) in series and then is connected with an ECU ground in the engine controller (4), and a PVC voltage detection point (7) connected with a signal acquisition point of the engine controller (4) is arranged between the PCV resistor (5) and the ECU resistor (6);
the OBD diagnosis method for the engine crankcase ventilation device comprises the following steps:
the first step is as follows: the diagnosis enables, and engine controller (4) gathers ignition key opening time signal, engine operation time signal, engine operating condition signal and storage battery voltage signal in real time, and engine controller (4) judges whether satisfies the enabling condition:
the first condition is as follows: the ignition key on time is greater than a set ignition key on time threshold;
and a second condition: the engine running time is greater than or equal to a set engine running time threshold;
and (3) carrying out a third condition: the engine is not in a starting state;
and a fourth condition: the battery voltage is greater than a set battery voltage minimum threshold;
and a fifth condition: the battery voltage is less than the set maximum threshold value of the battery voltage;
when all of the above 5 conditions are satisfied, then both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are yes, i.e., high level; when any one of the above 5 conditions is not satisfied, both the PCV circuit voltage diagnostic enable state and the PCV circuit voltage diagnostic enable condition state are non, i.e., low level;
the second step is that: the method comprises the steps of high-voltage diagnosis and low-voltage diagnosis, wherein an engine controller (4) collects a PCV loop voltage diagnosis enabling state signal and a PCV loop voltage diagnosis enabling condition state signal in real time, and simultaneously collects PCV loop voltage at a PVC voltage detection point (7) in real time;
high-pressure diagnosis: when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both yes, the engine controller (4) continuously compares the magnitude relation between the PCV circuit voltage and the PCV circuit voltage high threshold, when the PCV circuit voltage is greater than or equal to the PCV circuit voltage high threshold, a PCV circuit voltage high event is triggered, the PCV circuit voltage high event is triggered to be TRUE, the engine controller (4) starts to record the duration of PCV circuit voltage high fault _ pending, when the recorded PCV circuit voltage high fault _ pending duration exceeds the set threshold, the PCV circuit voltage high fault _ confirmed to be TRUE, the engine controller (4) confirms fault activation, and a visual warning system prompts a driver that the PCV is disconnected;
when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both not, assigning the value of the PCV circuit voltage diagnosis enabling state to the PCV circuit voltage high diagnosis enabling state, and assigning the value of the PCV circuit voltage diagnosis enabling condition state to the PCV circuit voltage high diagnosis enabling condition state, wherein the PCV circuit voltage high diagnosis enabling state and the PCV circuit voltage high diagnosis enabling condition state are both not, and after the PCV circuit voltage high diagnosis enabling state and the PCV circuit voltage high diagnosis enabling condition state are subjected to NOT logic, the duration time of the PCV circuit voltage high event is set to be zero and frozen, and the PCV open fault is not activated;
low-voltage diagnosis: when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both yes, the engine controller (4) continuously compares the magnitude relation between the PCV circuit voltage and the PCV circuit voltage low threshold, when the PCV circuit voltage is less than or equal to the PCV circuit voltage low threshold, a PCV circuit voltage low event is triggered, the PCV circuit voltage low event is triggered to be TRUE, the engine controller (4) starts to record the duration time of PCV circuit voltage low fault pending, when the recorded PCV circuit voltage low fault pending duration exceeds a set threshold, the PCV circuit voltage low fault is confirmed to be TRUE, the engine controller (4) confirms fault activation, and a visual warning system prompts a driver that the PCV is in short circuit with the ground;
when the PCV circuit voltage diagnosis enabling state and the PCV circuit voltage diagnosis enabling condition state are both not, the value of the PCV circuit voltage diagnosis enabling state is assigned to the PCV circuit voltage low diagnosis enabling state, and meanwhile, the value of the PCV circuit voltage diagnosis enabling condition state is assigned to the PCV circuit voltage low diagnosis enabling condition state, at the moment, the PCV circuit voltage low diagnosis enabling state and the PCV circuit voltage low diagnosis enabling condition state are both not, after the PCV circuit voltage low diagnosis enabling state and the PCV circuit voltage low diagnosis enabling condition state pass through NOT logic, the duration time of a PCV circuit voltage low event is set to be zero and frozen, and then the fault of PCV ground short circuit cannot be activated.
2. The electrical circuit-based engine crankcase ventilation (OBD) diagnostic method as claimed in claim 1, wherein:
connecting wires of the first contact switch (2) and the second contact switch (3) are embedded outside the ventilation pipe (1), the first contact switch (2) and the second contact switch (3) are both in a closed state when the ventilation pipe (1) is normally installed, the second contact switch (3) is disconnected when the left end of the ventilation pipe (1) falls off, and the first contact switch (2) is disconnected when the right end of the ventilation pipe (1) falls off.
3. An electrical circuit based engine crankcase ventilation device, OBD, diagnostic method according to claim 1 or 2, wherein:
the ignition key opening time points the time when the ignition key is placed in the ON gear.
4. The electrical circuit-based engine crankcase ventilation (OBD) diagnostic method of claim 3, wherein:
the engine running time refers to the duration of the engine starting from a stop state and after the engine passes a starting state and the engine speed is greater than a calibrated threshold value of the running state.
5. The electrical circuit-based engine crankcase ventilation (OBD) diagnostic method of claim 4, wherein:
the working state of the engine is judged according to the position of an ignition key and the rotating speed of the engine and is divided into four states of stopping, starting, running and flameout.
6. The electrical circuit-based engine crankcase ventilation (OBD) diagnostic method of claim 5, wherein:
the ignition key opening time threshold, the engine running time threshold, the battery voltage minimum threshold and the battery voltage maximum threshold are set values and can be changed according to different vehicle types.
7. The electrical circuit-based engine crankcase ventilation (OBD) diagnostic method of claim 5, wherein:
the PCV loop voltage high threshold and the PCV loop voltage low threshold are set voltage values and can be changed according to different vehicle types.
8. The electrical circuit-based engine crankcase ventilation (OBD) diagnostic method of claim 5, wherein:
the set threshold value of the PCV loop voltage high fault pending duration is an artificial set value and can be changed according to different vehicle types;
the set threshold value of the PCV loop voltage low fault pending duration is an artificial set value and can be changed according to different vehicle types.
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