CN113107673A

CN113107673A - Pipeline disconnection diagnosis method and device and electronic equipment

Info

Publication number: CN113107673A
Application number: CN202010032963.5A
Authority: CN
Inventors: 薄东; 程传辉; 杨辉; 吴迪; 李广乐; 韩珍
Original assignee: SAIC Motor Corp Ltd
Current assignee: SAIC Motor Corp Ltd
Priority date: 2020-01-13
Filing date: 2020-01-13
Publication date: 2021-07-13
Anticipated expiration: 2040-01-13
Also published as: CN113107673B

Abstract

The invention provides a method, a device and an electronic device for diagnosing disconnection of a pipeline, wherein if the preset intake flow deviation data output by an intake flow deviation model is larger than the intake flow deviation value of a cylinder, an intake flow change rate calculation rule corresponding to the initial running state of a vehicle is obtained; calculating to obtain an initial intake flow change rate according to the intake flow change rate calculation rule; the intake flow deviation data and the initial intake flow change rate represent the intake flow change conditions of the engine cylinder before and after the intake pipeline is switched on and off; and determining a diagnosis result of whether the air inlet pipeline is disconnected according to the comparison result of the initial air inlet flow change rate and the air inlet flow deviation value of the cylinder. By the invention, whether the air inlet pipeline is disconnected or not can be detected, and the dynamic property of the engine can be ensured in time.

Description

Pipeline disconnection diagnosis method and device and electronic equipment

Technical Field

The invention relates to the field of crankshaft ventilation system diagnosis, in particular to a method and a device for diagnosing disconnection of a pipeline and electronic equipment.

Background

With the increasingly strict emission requirements of the whole automobile, the pollutant emission limit value of the GB18352.6-201 light automobile and the measurement method clearly require the detection of the crankshaft ventilation system, and the air inflow of an engine cylinder can be influenced when a connecting pipeline in the crankshaft ventilation system is disconnected, so that the dynamic property of the engine is influenced.

Disclosure of Invention

In view of the above, the present invention provides a method, an apparatus and an electronic device for diagnosing a disconnection of a pipeline, so as to solve the problem that it is urgently needed to detect whether a ventilation connecting pipeline in a crankshaft ventilation system is disconnected.

In order to solve the technical problems, the invention adopts the following technical scheme:

a pipe disconnect diagnostic method comprising:

if the air intake flow deviation data output by the preset air intake flow deviation model is larger than the air intake flow deviation value of the cylinder, acquiring an air intake flow change rate calculation rule corresponding to the initial running state of the vehicle;

calculating to obtain an initial intake flow change rate according to the intake flow change rate calculation rule; the intake flow deviation data and the initial intake flow change rate represent the intake flow change conditions of the engine cylinder before and after the intake pipeline is switched on and off;

and determining a diagnosis result of whether the air inlet pipeline is disconnected according to the comparison result of the initial air inlet flow change rate and the air inlet flow deviation value of the cylinder.

Optionally, calculating an initial intake flow rate of change according to the intake flow rate calculation rule includes:

if the initial running state is flameout after the engine is started instantly or the engine is unstable in idle speed, calculating the initial intake air flow rate change rate corresponding to the initial running state of the vehicle; the inlet flowRate of change of quantity lambda_idleThe calculation formula of (2) is as follows:

wherein, is Δ Q_idleThe change value of the air intake flow of the engine cylinder before and after the air intake pipeline is switched on and off is obtained; the above-mentioned

The air inlet flow of the engine cylinder before the air inlet pipeline is switched on and off; said D^B→CIs the diameter of the flow restriction orifice in the part load tube; said D^A→CThe diameter of the part load tube; the intake line includes the part-load tube.

Optionally, determining a diagnosis result of whether the intake pipe is disconnected according to the comparison result of the initial intake flow rate change rate and the cylinder intake flow deviation value comprises:

executing an air inlet pipeline disconnection verification strategy corresponding to the initial running state of the vehicle, acquiring the current running state of the vehicle, and calculating the current air inlet flow change rate corresponding to the current running state of the vehicle according to the air inlet flow change rate calculation rule; the air intake pipeline disconnection verification strategy comprises controlling the engine to restart;

if the initial operation state and the current operation state are both flameout after the engine is started at the moment, the current intake flow change rate is still larger than the cylinder intake flow deviation value, and the difference value between the current intake flow change rate and the intake flow deviation data output by the preset intake flow deviation model is within a preset data range, outputting a result representing the disconnection of part of load tubes in a crankshaft ventilation system;

and if the initial operation state and the current operation state are both unstable engine idle speed, the current intake flow change rate is still greater than the cylinder intake flow deviation value, and the difference value between the current intake flow deviation value and the intake flow deviation data output by the preset intake flow deviation model is within a preset data range, outputting a result representing the disconnection of part of load tube parts in a crankshaft ventilation system.

if the initial running state is normal idle speed and the vehicle speed is less than a preset threshold value, calculating an initial intake air flow change rate corresponding to the initial running state of the vehicle; the initial intake air flow rate of change λ_idleThe calculation formula of (2) is as follows:

wherein, is Δ Q_PartloadThe change value of the air intake flow of the engine cylinder before and after the air intake pipeline is switched on and off is obtained; said Q_FlowmeterThe air inlet flow of the engine cylinder before the air inlet pipeline is switched on and off; said D^E→DThe size of the flow-limiting hole of the full-load tube; d is the aperture of a clean air inlet pipe at the joint of the crankshaft ventilation system and the full-load pipe; the air inlet pipeline comprises the partial load pipe and a full load pipe.

executing an air inlet pipeline disconnection verification strategy corresponding to the initial running state of the vehicle, acquiring the current running state of the vehicle, and calculating the current air inlet flow change rate corresponding to the current running state of the vehicle according to the air inlet flow change rate calculation rule; the air inlet pipeline disconnection verification strategy comprises the steps of respectively controlling the vehicles to run at different speeds or different gears, and obtaining the current running state of the vehicle corresponding to each speed;

calculating the current intake air flow change rate corresponding to the current running state of the vehicle corresponding to each vehicle speed according to the intake air flow change rate calculation rule corresponding to the current running state of the vehicle corresponding to each vehicle speed; the calculation formula of the current intake air flow rate of change is as follows:

and if the current running state of the vehicle corresponding to each vehicle speed is that the engine is in normal idling and the vehicle speed is less than a preset threshold value, the current intake air flow change rate corresponding to each vehicle speed is still greater than the cylinder intake air flow deviation value, and the difference value between the current intake air flow change rate and the intake air flow deviation data output by the preset intake air flow deviation model is within a preset data range, outputting a result representing the disconnection of a full load tube part in the crankshaft ventilation system.

A pipe disconnection diagnostic device comprising:

the rule obtaining module is used for obtaining an intake flow change rate calculation rule corresponding to the initial running state of the vehicle if intake flow deviation data output by the preset intake flow deviation model is larger than the intake flow deviation value of the cylinder;

the change rate calculation module is used for calculating to obtain an initial intake flow change rate according to the intake flow change rate calculation rule; the intake flow deviation data and the initial intake flow change rate represent the intake flow change conditions of the engine cylinder before and after the intake pipeline is switched on and off;

and the diagnosis module is used for determining the diagnosis result of whether the air inlet pipeline is disconnected according to the comparison result of the initial air inlet flow change rate and the air inlet flow deviation value of the cylinder.

Optionally, the change rate calculation module is configured to, when calculating the initial intake flow change rate according to the intake flow change rate calculation rule, specifically:

if the initial running state is flameout after the engine is started instantly or the engine is unstable in idle speed, calculating the initial intake air flow rate change rate corresponding to the initial running state of the vehicle; the intake flow rate of change λ_idleThe calculation formula of (2) is as follows:

wherein, is Δ Q_idleIs the air inlet pipeline passageThe change value of the air intake flow of the engine cylinder before and after the interruption; the above-mentioned

Optionally, the diagnostic module comprises:

the first change rate calculation submodule is used for executing an air inlet pipeline disconnection verification strategy corresponding to the initial running state of the vehicle, acquiring the current running state of the vehicle and calculating the current air inlet flow change rate corresponding to the current running state of the vehicle according to the air inlet flow change rate calculation rule; the air intake pipeline disconnection verification strategy comprises controlling the engine to restart;

the first diagnosis sub-module is used for outputting a result representing disconnection of part of load tubes in a crankshaft ventilation system if the initial operation state and the current operation state are flameout after the engine is started, the current intake flow change rate is still greater than the cylinder intake flow deviation value, and the difference value between the current intake flow change rate and the intake flow deviation data output by the preset intake flow deviation model is within a preset data range;

and the second diagnosis sub-module is used for outputting a result representing the disconnection of part of load tube parts in the crankshaft ventilation system if the initial operation state and the current operation state are both unstable engine idle speed, the current intake flow change rate is still greater than the cylinder intake flow deviation value, and the difference value between the current intake flow deviation rate and the intake flow deviation data output by the preset intake flow deviation model is within a preset data range.

if the initial running state is normal idle speed and the vehicle speed is less than a preset threshold value, calculating the initial running state of the vehicleThe initial intake air flow rate of change corresponding to the initial running state; the initial intake air flow rate of change λ_idleThe calculation formula of (2) is as follows:

Optionally, the diagnostic module comprises:

the second change rate calculation submodule is used for executing an air inlet pipeline disconnection verification strategy corresponding to the initial running state of the vehicle, acquiring the current running state of the vehicle and calculating the current air inlet flow change rate corresponding to the current running state of the vehicle according to the air inlet flow change rate calculation rule; the air inlet pipeline disconnection verification strategy comprises the steps of respectively controlling the vehicles to run at different speeds or different gears, and obtaining the current running state of the vehicle corresponding to each speed;

the third change rate calculation submodule is used for calculating the current intake air flow change rate corresponding to the current running state of the vehicle corresponding to each vehicle speed according to the intake air flow change rate calculation rule corresponding to the current running state of the vehicle corresponding to each vehicle speed; the calculation formula of the current intake air flow rate of change is as follows:

and the third diagnosis sub-module is used for outputting a result representing the disconnection of a full load tube part in the crankshaft ventilation system if the current running state of the vehicle corresponding to each vehicle speed is that the engine idling is normal, the vehicle speed is less than a preset threshold value, the current intake flow change rate corresponding to each vehicle speed is still greater than the cylinder intake flow deviation value, and the difference value between the current intake flow change rate and the intake flow deviation data output by the preset intake flow deviation model is within a preset data range.

An electronic device, comprising: a memory and a processor;

wherein the memory is used for storing programs;

the processor calls a program and is used to:

Compared with the prior art, the invention has the following beneficial effects:

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic view of a scenario of a method for diagnosing a disconnection of a pipeline according to an embodiment of the present invention;

fig. 2 is a schematic view of another pipeline disconnection diagnosis method according to an embodiment of the present invention;

fig. 3 is a schematic view of a scenario of another method for diagnosing a disconnection of a pipeline according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a method for diagnosing a pipe disconnection according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a pipe disconnection diagnosing apparatus according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a crankshaft ventilation system, which includes a clean air inlet pipe, a full load pipe, a partial load pipe, a crankcase, an air inlet manifold and the like, wherein the clean air inlet pipe is connected with a throttle valve of a vehicle, air output by the throttle valve of the engine flows into the full load pipe through the clean air inlet pipe, the full load pipe reaches the partial load pipe through the crankcase, flows into the air inlet manifold, and flows into cylinders of the engine of the vehicle through the air inlet manifold.

The engine is divided into a single breathing pipe system and a multi-breathing pipe system, the engine of the single breathing pipe system only has a partial load pipe and does not have a full load pipe, namely, a crankshaft ventilation pipeline has a gas flow direction (A → C) and a crankshaft ventilation pipeline has no (D → F) pipeline. When the engine with the multi-breathing pipe system is provided with a partial load pipe and a full load pipe, the gas flow directions of the crankshaft ventilation pipeline are (D → F) and (A → C).

The inventor finds that the crankshaft ventilation system can provide air power for the engine cylinder, and the performance of the crankshaft ventilation system directly influences the air inflow of the cylinder of the engine, and further influences the dynamic performance of the engine. The pressure sensor can be added at the crankcase cover in the crankshaft ventilation system, and the pressure in the crankcase can be detected according to the vacuum characteristic of the crankcase pressure, so that the basis is provided for the performance improvement of the dynamic property of the engine. However, the pressure sensor is provided in such a manner that the value detected by the pressure sensor is within a certain range regardless of whether the connecting line is open or closed, i.e., the pressure sensor is provided in such a manner that it is not possible to diagnose whether the connecting line in the crank ventilation system is open or closed. In order to achieve this, the inventors have found that a preset intake flow deviation model can be generated which, by analyzing the flow meter into the clean air line and the actual flow into the engine cylinders, yields whether the intake line in the crankshaft ventilation system is disconnected, but it is not possible to determine whether the partial load line or the full load line is disconnected. For this reason, the inventors have further studied and found the following:

calculating the gas flow passing through the crankshaft ventilation system pipeline according to the energy conservation principle and the related principle in the fluid mechanics, setting the sections at the two ends of the crankshaft ventilation pipeline as section 1(ACDF is a section, which may be a in this embodiment) and section 2 (which may be C in this embodiment), respectively, and the corresponding bernoulli equation is as follows:

in the formula P₁Pressure (Pa), v) at a certain point in the fluid of section 1₁Flow velocity (m/s), h, of a fluid having a cross section 1₁Is the height of the point of section 1, P₂Pressure (Pa), v) at a certain point in the fluid of section 2₂The flow velocity (m/s) at that point of the fluid for a certain cross-section 2, and ρ is the fluid density (kg/m)³) G is the acceleration of gravity, h₂C is a constant value for the height of the section 2 at which this point is located.

As the breathing pipe pipelines (such as a partial load pipe and a full load pipe) of the crankshaft ventilation system are in the same terrain, the head loss is consistent, namely h₁＝h₂Therefore, the bernoulli equation at the two ends of the pipeline is changed as follows:

the pressure at which the gases flow in the crankcase ventilation system line is defined as the total pressure, and the value measured by means of a pressure sensor arranged at the crankcase cover is referred to as the static pressure P₂And the gas flow velocity near the wall surface at the line static pressure measurement location is approximately v₂The total pressure corresponding to the cross section 2 can be found from the formula (2) when it is 0

The gas flow of the crankshaft ventilation pipeline can be measured by a Blow-by (air leakage) measuring instrument, and the corresponding gas flow velocity calculation formula is as follows:

wherein q is the intake air flow (kg/s), A is the area of the pipeline, and D is the diameter (m) of the pipeline.

According to the formula (3) and the formula (4), the average total pressure of the section 1 of the crankshaft ventilation pipeline is calculated as follows:

the working conditions of the engine are divided into an idling working condition, a low-speed working condition and a high-speed working condition, and under the condition that an air inlet pipeline in a crankshaft ventilation system is not disconnected, the method for calculating the air inlet flow of an engine cylinder under each working condition is respectively introduced:

1. method for calculating air intake flow under idle working condition of engine

As shown in FIG. 1, when the engine is idling, the leakage rate of the intake manifold itself is set to zero, the throttle valve of the engine is closed at idling, and the flow rate of intake air actually entering the cylinder of the engine is calculated as follows

Q_idle＝Q_Throttle+Q_PCV＝Q_Throttle+Q_Freshair+Q_Blowby (6)

Wherein Q is_idleTotal air input into the engine cylinder at idle speed, Q_ThrottleFor allowing a leakage flow of gas directly into the cylinder without passing through the crankcase after the throttle has been closed (this flow is given by the supplier when the sample is supplied), Q_PCVFor the gas flow through the crankshaft ventilation system into the cylinder, the flow consists of two parts, one part being the leakage Q of the crankshaft ventilation system of the vehicle_BlowbyThe other part is the fresh air flow Q entering the crankshaft ventilation system through a clean air inlet pipeline_Freshair。

For an engine with a single exhalation tube system, the crankshaft vent line gas flow direction (A → C) is absent (D → F) line, at which time Q_FreshairWhen the idle speed is equal to 0L/min, the total flow rate is

Q_idle＝Q_Throttle+Q_PCV＝Q_Throttle+Q_Blowby (7)

The idling air inflow at this time is allowed to enter the gas leakage flow Q of the cylinder directly without passing through the crankcase after the valve is closed_ThrottleAir leakage Q with crankshaft ventilation system of vehicle_BlowbyAnd (6) determining.

Engine for multi-breathing tube systemThe crankshaft ventilation circuit gas flow directions are (A → C) and (D → F), and the gas flow rate Q into the cylinder through the crankshaft ventilation system in the total idle flow rate (6)_PCVFurther calculations are required.

The end surface A of a part of load pipeline of a crankshaft ventilation system is set to be a section 1, the end surface C is set to be a section 2, the pressure difference at the two ends is delta P, the formula (2) shows that,

due to idling of the engine, P₁＞P₂However, | P₂L is much greater than | P₁|，v₁Is much less than v₂Thus v is₁Is approximately equal to 0, and the formula is simplified into

The minimum aperture diameter of a certain section of the crankshaft ventilation pipeline is set to be D, so that the gas flow Q entering the cylinder through the crankshaft ventilation system_PCVIs composed of

According to the formula (10), when the engine of the multi-breathing pipe system is idling, the gas flow Q entering the air inlet manifold and the air cylinder through the crankshaft ventilation system_PCV∝D²When the diameter of the pipe diameter is enlarged, the gas flow rate is multiplied.

2. Engine low speed operating mode intake air flow calculation

Aiming at the low-speed and low-load working condition of the engine, the leakage quantity of the air intake manifold is set to be zero, a small part of the throttle valve of the engine is opened, and the pressure P of the air intake manifold is set to be zero_Manifold< 0, at which time the gas flow Q measured from the air filter rear end intake air flow meter (disposed in the clean intake line) is_Flowmeter(i.e., engine cylinder intake air flow rate before intake line is turned on/off), where Q_FlowmeterOne part of the air (D → F) flowing through the crankshaft ventilation system enters the crankshaft ventilation system, the other part of the air enters the throttle valve through the clean air inlet pipe, and Q_Flowmeter＝Q_Throttle+Q_PCVWhen the total flow of gas entering the engine cylinder is

Q_Partload＝Q_Throttle+Q_PCV+Q_Blowby＝Q_Flowmeter+Q_Blowby (11)

Wherein Q is_PartloadThe total flow of gas into the engine cylinder at part load conditions.

3. Method for calculating air intake flow under high-speed working condition of engine

When aiming at the high-speed high-load working condition of the engine, the leakage quantity of the air inlet manifold is set to be zero, and most of the throttle valve of the engine is opened:

for naturally aspirated engines P_Manifold< 0, the total flow of gas into the engine cylinder is calculated according to equation (11);

for supercharged engines P_ManifoldGreater than 0, gas flow Q entering from the air filter rear end flowmeter_FlowmeterAll flow through the throttle, thus Q_Flowmeter＝Q_ThrottleAnd the total flow of gas into the engine cylinder at this time is

Q_Fullload＝Q_Throttle+Q_Blowby＝Q_Flowmeter+Q_Blowby (12)

Wherein Q_FullloadThe total flow of gas into the engine cylinder at high or full load conditions.

Q in the engine can be found from the equations (11) and (12)_FlowmeterThe air intake flow of the corresponding working condition can be read through the control parameters of the engine ECU.

In the case of a disconnected intake air line in a crankshaft ventilation system, the method for calculating the intake air flow of an engine cylinder under each operating condition is described:

1. intake flow calculation method after disconnection of connecting pipeline of crankshaft ventilation system

As shown in FIG. 2, the tube connection is made for the partial load tube (A → C)Disconnected at connection B, when the engine is idling, and Q_BlowbyConstant, the flow rate of the engine PCV system into the intake manifold when the part load tube (A → C) is not disconnected is marked as

(it can also be called the air intake flow of the engine cylinder before the air intake pipeline is switched on and off), and the flow of the PCV system of the engine entering the air intake manifold when the pipeline (A → C) is switched off is

According to the formula (6), the increased gas flow quantity delta Q entering the engine when the partial load pipe is disconnected is larger than that when the partial load pipe is not disconnected_idle(namely the intake air flow change value of the engine cylinder before and after the air inlet pipeline is switched on and off) is calculated as follows:

Equation (13) is therefore modified as follows:

as shown in FIG. 3, for a full load circuit (D → F) tube connection E disconnection, where the pressure is atmospheric, the air flow rate can be considered approximately ideally as v_EIs approximately equal to 0, therefore, according to the formulas (8) and (9), the gas flow entering the engine crankcase from the position E and the gas flow entering the clean air inlet pipeline from the position E can be respectively calculated according to the formula (10) to obtain the corresponding respiratory tube flow Q_PCV。

When the engine works at a low speed and a small load, the manifold pressure is negative pressure, the flow direction of the gas in the full-load pipeline of the crankshaft ventilation system is E → F, E → D, and the gas flow increment entering the engine (namely the intake air flow change value of the engine cylinder before and after the intake pipeline is switched) is known according to the formula (11) when the full-load pipeline (D → F) is switched off and is not switched off:

when the engine is in high-speed and high-load operation, the manifold pressure is positive, and the flow directions of the full-load pipeline gas of the crankshaft ventilation system are F → E, E → D, wherein

As can be measured by Blow-by, and is also approximately equivalent to the flow caused by the F-E tube pressure differential, from equation (12), the incremental flow of gas into the engine occurs when the full load circuit (D → F) is disconnected, as compared to before disconnection:

the method for calculating the intake air flow of the engine cylinder under each condition when the air inlet pipeline in the crankshaft ventilation system is not disconnected and is disconnected is described, and how to determine whether the respiratory pipe is disconnected or not and the deviation value of the intake air flow of the engine cylinder when the air inlet pipeline is not disconnected and is disconnected are described.

1. On Board Diagnostics (OBD) diagnosis of intake flow model deviation after partial load breathing tube disconnection

The part load breathing tube functions in the same way whether the single breathing tube engine or the multi-breathing tube engine is the one in which gas enters the intake manifold from the crankcase when the intake manifold is at negative pressure, and most of the single breathing tube vehicle arrangements are integrated into the cylinder cover without the problem of the disconnection of the pipeline, so that the OBD diagnosis is not needed, but the OBD diagnosis of the breathing tube which is not integrated into the cylinder cover, such as the (A → C) tube in FIG. 1, is analyzed as follows.

When the engine is idling, the PCV (positive crankcase ventilation) air supplement amount accounts for the total intake air amountA certain proportion, therefore, when the pipe (A → C) is disconnected, the proportion lambda of the increased gas flow to the air supplement quantity of the original crank ventilation PCV system can be known according to the formulas (6), (10) and (14)_idleThe calculation is as follows,

Because of the flow limiting hole function of the engine partial load tube, the diameter of the partial load tube is larger than that of the flow limiting hole, and the limit hypothesis D is taken^B→C＞＞2D^A→CAs can be seen from the formula (17), λ_idle＝∞>Set deviation value of intake air flow of cylinder

Therefore, when the engine is idling and the partial load pipe is disconnected, the air inflow rate entering the engine is infinitely increased and exceeds the air inflow rate deviation value of the cylinder

And (4) carrying out OBD diagnosis.

2. OBD diagnosis of intake flow model deviation after disconnection of full-load respiratory siphon

The engine runs under the low-speed and low-load working condition, the diameter of the pipeline of the clean air inlet pipe is D, and the pressure difference of the clean air inlet pipe of the engine at the position of the full-load pipe is delta P_{Air inlet pipe}When the engine runs under the working condition of low speed and small load, the full load pipeline is disconnected, D^E→F＝D^D→FAt this time, | Δ P can be approximately considered^E-D|≈|ΔP^E-F|≈|ΔP^D-F|≈|ΔP_{Intake air}L, so that equation (15) is modified to

According to the formulas (11) and (18), when the engine runs at low speed and under small load, the proportion of the air inflow of the crankshaft ventilation system to the total air inflow is small, and when the pipeline (D → F) is disconnected, the increased air flow accounts for the air inflow Q according to the formulas (10) and (18)_FlowmeterRatio of (A)_partloadThe calculation is as follows,

Thus setting a deviation value of the intake air flow of the cylinder

Need to satisfy

It may be used as a diagnostic to determine crankshaft ventilation system OBD.

In order to ensure the effectiveness of judgment, three (two or more) low-speed and low-load working conditions are respectively selected from the engine operation working conditions and simultaneously meet the requirement of judgment

The diagnosis of full load pipe disconnection is used as the OBD diagnosis control strategyBut not shown.

In summary, the inventor finds a corresponding relationship between different working conditions (start-up flameout, unstable idling and normal idling, and the vehicle speed is less than a preset vehicle speed threshold) and an intake flow rate calculation rule, and through the corresponding relationship, the intake flow rate under different working conditions can be calculated, if the intake flow rate is greater than a preset cylinder intake flow deviation value, it can be determined that an intake pipe in a crankshaft ventilation system is disconnected, and according to a specific working condition, it is further determined whether a partial load pipe is disconnected or a full load pipe is disconnected.

Specifically, an embodiment of the present invention provides a method for diagnosing disconnection of a pipeline, and referring to fig. 4, the method may include: and S11, if the air intake flow deviation data output by the preset air intake flow deviation model is larger than the air intake flow deviation value of the cylinder, acquiring an air intake flow change rate calculation rule corresponding to the initial running state of the vehicle.

In practical application, the preset intake air flow deviation model is generated in advance, whether the intake pipe in the crankshaft ventilation system is disconnected or not is obtained by analyzing the flow meter entering the clean air pipe and the actual flow entering the engine cylinder, if the intake air flow deviation data output by the preset intake air flow deviation model is larger than the cylinder intake air flow deviation value (namely, the value R), the intake pipe (including a full load pipe or a partial load pipe) is considered to be disconnected, and at this time, in general, when the pipe of the full load pipe is arranged,

the value of (b) will be greater than R. The intake air flow deviation data in the embodiment represents the change of the intake air flow of the engine cylinder before and after the intake pipe is turned on and off, and the change in the embodiment may be a change rate.

The vehicle working conditions have three working conditions (namely initial running states) which are respectively flameout (starting flameout), unstable idling (unstable idling of the engine) and normal idling after the engine is started and the vehicle speed is less than a preset threshold value.

Under two working conditions of flameout (starting flameout) after the engine is started instantly and unstable idle speed, whether a part of load tubes are disconnected or not can be determined, and whether a full load tube is disconnected or not can be determined when the idle speed is normal and the vehicle speed is less than a preset threshold value.

The intake air flow rate of change calculation rules that different vehicle operating modes correspond are different, and in practical application, the intake air flow rate of change calculation rules that the engine stalls (starts to stall) after the moment of starting are:

In practical application, the engine flameout (start flameout) after the moment of starting the engine can also be used as an idle state, and then the intake air flow rate change calculation rules corresponding to two working conditions of the flameout (start flameout) after the moment of starting the engine and the unstable idle state are the same, but when the flameout (start flameout) after the moment of starting the engine is carried out, due to the effect of the flow limiting holes of part of the load tubes of the engine, the diameters of the holes of general part of the load tubes are larger than the diameter of the flow limiting holes, and the limit^B→C＞＞2D^A→CAs can be seen from the formula (17), λ_idle＝∞。

The intake air flow rate change calculation rule corresponding to the idling instability is as follows:

under the working condition of unstable idling, the connecting pipeline may have an incomplete disconnection state directly according to

And calculating to obtain the intake flow change rate.

When the idling speed is normal and the vehicle speed is less than the preset threshold value, the intake air flow rate of change calculation rule is as follows:

And S12, calculating to obtain an initial intake flow rate of change according to the intake flow rate of change calculation rule. And the intake flow deviation data and the initial intake flow change rate represent the intake flow change conditions of the engine cylinder before and after the air inlet pipeline is switched on and switched off.

In practical application, if the ECU detects the initial operating state, the intake flow rate calculation rule corresponding to the initial operating device is directly called, and the initial intake flow rate change rate can be obtained by determining each parameter value in the intake flow rate change rate calculation rule, and the intake flow deviation data and the initial intake flow rate change rate represent the intake flow rate change of the engine cylinder before and after the intake pipe is turned on and off, where the change may be the change rate in this embodiment.

And S13, determining the diagnosis result of whether the air inlet pipeline is disconnected according to the comparison result of the initial air inlet flow change rate and the cylinder air inlet flow deviation value.

In this embodiment, if the initial intake air flow rate of change is greater than the cylinder intake air flow deviation value and the difference between the initial intake air flow rate of change and the intake air flow deviation data output by the preset intake air flow deviation model is within the preset data range, the intake pipeline may be considered to be disconnected primarily. In practical application, however, the engine can be retriggered to verify whether the air inlet pipeline is really disconnected or not under a certain working condition. Taking different working conditions, i.e. different initial operating states, as an example, the following specific implementation process of step S13 is described in detail:

if the initial operating state of the vehicle is flameout after the engine starting moment or unstable engine idle speed, step S13 may include:

1) executing an air inlet pipeline disconnection verification strategy corresponding to the initial running state of the vehicle, acquiring the current running state of the vehicle, and calculating the current air inlet flow change rate corresponding to the current running state of the vehicle according to the air inlet flow change rate calculation rule; the intake conduit disconnection verification strategy includes controlling the engine to restart.

In practical application, if the initial operation state is flameout after the engine starting moment, at this time, it may be considered that the partial load tube is disconnected, but it is necessary to further determine whether the partial load tube is actually disconnected, at this time, the engine is controlled to be started again, and if the engine is still flameout after the engine starting moment, the engine is flameout according to the above criteria

Calculating the current air inflow rate of change at the moment, if the current air inflow rate of change is lambda_idleInfinity, i.e. greater than

And when the air intake flow deviation data output by the preset air intake flow deviation model is in a preset numerical range, considering that part of the load tubes are disconnected, and outputting a result representing the disconnection of the part of the load tubes in the crankshaft ventilation system.

If the initial operation state is that the engine idle speed is unstable, the engine is controlled to start again, if the engine is still unstable in the idle speed, and the engine is started again according to the unstable idle speed

Calculating the current air intake flow change rate at the moment, and if the current air intake flow change rate is larger than the air intake flow deviation value of the cylinder

And when the air intake flow deviation data output by the preset air intake flow deviation model is in a preset numerical range, the full load pipe is considered to be disconnected, and at the moment, a result representing the disconnection of part of load pipes in the crankshaft ventilation system is output.

2) And if the initial running state and the current running state are both flameout after the engine is started instantly, the current intake flow change rate is still greater than the cylinder intake flow deviation value, and the difference value between the current intake flow change rate and the intake flow deviation data output by the preset intake flow deviation model is within a preset data range, outputting a result representing the disconnection of part of load tubes in the crankshaft ventilation system.

3) And if the initial operation state and the current operation state are both unstable engine idle speed, the current intake flow change rate is still greater than the cylinder intake flow deviation value, and the difference value between the current intake flow deviation value and the intake flow deviation data output by the preset intake flow deviation model is within a preset data range, outputting a result representing the disconnection of part of load tube parts in a crankshaft ventilation system.

If the initial operating state of the vehicle is idle and the vehicle speed is less than the preset threshold, step S13 may include:

1) executing an air inlet pipeline disconnection verification strategy corresponding to the initial running state of the vehicle, acquiring the current running state of the vehicle, and calculating the current air inlet flow change rate corresponding to the current running state of the vehicle according to the air inlet flow change rate calculation rule; the air inlet pipeline disconnection verification strategy comprises the steps of respectively controlling the vehicles to run at different speeds or different gears, and obtaining the current running state of the vehicle corresponding to each speed.

2) Calculating the current intake air flow change rate corresponding to the current running state of the vehicle corresponding to each vehicle speed according to the intake air flow change rate calculation rule corresponding to the current running state of the vehicle corresponding to each vehicle speed; the calculation formula of the current intake air flow rate of change is as follows:

3) and if the current running state of the vehicle corresponding to each vehicle speed is that the engine is in normal idling and the vehicle speed is less than a preset threshold value, the current intake air flow change rate corresponding to each vehicle speed is still greater than the cylinder intake air flow deviation value, and the difference value between the current intake air flow change rate and the intake air flow deviation data output by the preset intake air flow deviation model is within a preset data range, outputting a result representing the disconnection of a full load tube part in the crankshaft ventilation system.

In practical application, if the initial running state of the vehicle is normal idle speed and the vehicle speed is less than a preset threshold value, if the current intake air flow change rate is still greater than the cylinder intake air flow deviation value and the difference value between the current intake air flow change rate and the intake air flow deviation data output by the preset intake air flow deviation model is within a preset data range, the disconnection of the full-load pipe can be preliminarily considered, but in order to further determine whether the full-load pipe is disconnected, the vehicle can be controlled to run under different working conditions, namely different vehicle speeds or different gears, and then the disconnection of the full-load pipe is determined according to the conditions

And calculating to obtain the current intake flow change rate under each working condition, wherein each working condition corresponds to the current running state of the vehicle, and if the current running state of the vehicle is that the engine is in normal idle speed and the vehicle speed is less than a preset threshold value, the current intake flow change rate corresponding to each vehicle speed is still greater than the cylinder intake flow deviation value, and the difference value between the current intake flow change rate and the intake flow deviation data output by the preset intake flow deviation model is within a preset data range, considering that the full load tube is disconnected, and outputting a result representing the disconnection of the full load tube part in the crankshaft ventilation system.

In another implementation manner of the invention, the working conditions with different vehicle speeds or different gears can be verified in sequence, if one working condition passes the verification, the next working condition verification is executed, for example, when the idle speed is normal, the intake air flow change rate is greater than the intake air flow deviation value of the cylinder under any working condition when the vehicle speed at the gear a is less than 60km, and the disconnection of the full load pipe is suspected.

For checking the authenticity of a full-load tube release, the vehicle speed is set in gear b<At any working condition of 60km, further calculation is carried out

If the current running states are that the engine is in normal idling and the vehicle speed is less than a preset threshold value, the current intake flow change rate corresponding to each vehicle speed is still greater than the cylinder intake flow deviation value, and the difference value between the current intake flow change rate and the intake flow deviation data output by the preset intake flow deviation model is within a preset data range, the disconnection of the full load tube is confirmed;

to confirm again the authenticity of the full-load tube disconnection, the vehicle speed is in gear c<At any working condition of 60km, further calculation is carried out

Confirming that the current running states are normal idling of the engine and the vehicle speed is smaller than a preset threshold value, the current intake flow change rate corresponding to each vehicle speed is still larger than the cylinder intake flow deviation value, and the difference value between the current intake flow change rate and the intake flow deviation data output by the preset intake flow deviation model is within a preset data range, and confirming that the full load tube is disconnected;

if the steps are verified, the full-load pipe can be confirmed to have air leakage or disconnection risk, and then the OBD diagnosis can give an alarm.

If the initial intake air flow change rate is not larger than the cylinder intake air flow deviation value under each working condition, the OBD diagnosis warning of the crankshaft ventilation system can not be given.

In the embodiment, if the air intake flow deviation data output by the preset air intake flow deviation model is larger than the air intake flow deviation value of the cylinder, an air intake flow change rate calculation rule corresponding to the initial running state of the vehicle is obtained; calculating to obtain an initial intake flow change rate according to the intake flow change rate calculation rule; the intake flow deviation data and the initial intake flow change rate represent the intake flow change conditions of the engine cylinder before and after the intake pipeline is switched on and off; and determining a diagnosis result of whether the air inlet pipeline is disconnected according to the comparison result of the initial air inlet flow change rate and the air inlet flow deviation value of the cylinder. By the aid of the method and the device, whether the air inlet pipeline is disconnected or not can be detected, and OBD diagnosis of the connecting pipeline of the crankshaft ventilation system can be made, so that dynamic property of an engine can be guaranteed in time.

In addition, the OBD diagnosis method can quickly set the deviation of the air inlet model through the pipe diameter of the connecting pipeline of the crankshaft ventilation system

The vehicle speed is input to an OBD diagnosis control boundary by a model deviation when the engine is idling or the vehicle speed is low after the vehicle is started

The method can judge whether a part load pipeline and a full load connecting pipeline of the crankshaft ventilation system are disconnected or not by comparing with the actual air inflow, and further completes the diagnosis of the exhaust OBD of the system.

Optionally, on the basis of the above embodiment of the pipe disconnection diagnosis method, another embodiment of the present invention provides a pipe disconnection diagnosis apparatus, and with reference to fig. 5, the apparatus may include:

the rule obtaining module 11 is configured to obtain an intake air flow change rate calculation rule corresponding to an initial operating state of the vehicle if intake air flow deviation data output by the preset intake air flow deviation model is greater than the cylinder intake air flow deviation value;

the change rate calculation module 12 is configured to calculate an initial intake air flow change rate according to the intake air flow change rate calculation rule; the intake flow deviation data and the initial intake flow change rate represent the intake flow change conditions of the engine cylinder before and after the intake pipeline is switched on and off;

and the diagnosis module 13 is used for determining a diagnosis result of whether the air inlet pipeline is disconnected according to the comparison result of the initial air inlet flow change rate and the cylinder air inlet flow deviation value.

Further, the change rate calculation module is configured to, when calculating the initial intake flow change rate according to the intake flow change rate calculation rule, specifically:

Further, the diagnostic module comprises:

Further, the diagnostic module comprises:

It should be noted that, for the working processes of each module and sub-module in this embodiment, please refer to the corresponding description in the above embodiments, which is not described herein again.

Optionally, on the basis of the above embodiment of the method and apparatus for diagnosing a pipe disconnection, another embodiment of the present invention provides an electronic device, including: a memory and a processor;

wherein the memory is used for storing programs;

the processor calls a program and is used to:

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of diagnosing disconnection of a pipe, comprising:

2. The pipe disconnection diagnostic method according to claim 1, wherein calculating an initial intake flow rate of change in accordance with the intake flow rate of change calculation rule includes:

The air inlet flow of the engine cylinder before the air inlet pipeline is switched on and off; said D^B→CIs the diameter of the flow restriction orifice in the part load tube; said D^A ^→CThe diameter of the part load tube; the intake line includes the part-load tube.

3. The conduit disconnection diagnostic method according to claim 2, wherein determining a diagnostic result of whether an intake conduit is disconnected based on a comparison of the initial intake flow rate change rate with the cylinder intake flow deviation value comprises:

4. The pipe disconnection diagnostic method according to claim 1, wherein calculating an initial intake flow rate of change in accordance with the intake flow rate of change calculation rule includes:

if the initial running state is normal idle speed and the vehicle speed is less than the preset valueA threshold value that calculates an initial intake air flow rate of change corresponding to an initial operating state of the vehicle; the initial intake air flow rate of change λ_idleThe calculation formula of (2) is as follows:

5. The conduit disconnection diagnostic method of claim 4, wherein determining a diagnostic result of whether an intake conduit is disconnected based on a comparison of the initial intake flow rate change rate and the cylinder intake flow deviation value comprises:

6. A pipe disconnection diagnostic device, comprising:

7. The pipe disconnection diagnostic device according to claim 6, wherein the change rate calculation module is configured to, when calculating the initial intake flow rate change according to the intake flow rate change rate calculation rule, specifically:

wherein，ΔQ_idleThe change value of the air intake flow of the engine cylinder before and after the air intake pipeline is switched on and off is obtained; the above-mentioned

8. The conduit disconnect diagnostic device of claim 7, wherein the diagnostic module comprises:

9. The pipe disconnection diagnostic device according to claim 6, wherein the change rate calculation module is configured to, when calculating the initial intake flow rate change according to the intake flow rate change rate calculation rule, specifically:

10. The conduit disconnect diagnostic device of claim 9, wherein the diagnostic module comprises:

the third change rate calculation submodule is used for calculating the current intake air flow change rate corresponding to the current running state of the vehicle corresponding to each vehicle speed according to the intake air flow change rate calculation rule corresponding to the current running state of the vehicle corresponding to each vehicle speed; the calculation of the current intake air flow rate of change is disclosedThe formula is as follows:

11. An electronic device, comprising: a memory and a processor;

wherein the memory is used for storing programs;

the processor calls a program and is used to: