阅读说明：本技术 管路断开检测方法 (Pipeline disconnection detection method ) 是由 贾维新 牟江峰 于 2017-09-07 设计创作，主要内容包括：本发明提供了一种管路断开检测方法,应用在基于导电回路机理的管路断开检测系统,用于检测曲轴箱通风管路系统是否断开。所述管路断开检测系统包括断开检测线路,所述断开检测线路的两端分别与ECU单元的电源端和接地端相连。所述断开检测线路上设有用于诊断所述断开检测线路是否发生短路的电阻单元。所述管路断开检测方法包括：检测待检测点的电信号；根据所述待检测点的电信号判断所述断开检测线路是否发生短路。本发明能够提高对曲轴箱通风管路系统断开检测的准确性。(The invention provides a pipeline disconnection detection method which is applied to a pipeline disconnection detection system based on a conductive loop mechanism and used for detecting whether a crankcase ventilation pipeline system is disconnected or not. The pipeline disconnection detection system comprises a disconnection detection line, and two ends of the disconnection detection line are respectively connected with a power supply end and a grounding end of the ECU unit. And the disconnection detection line is provided with a resistance unit for diagnosing whether the disconnection detection line is short-circuited or not. The pipeline disconnection detection method comprises the following steps: detecting an electric signal of a point to be detected; and judging whether the disconnection detection line is short-circuited or not according to the electric signal of the point to be detected. The invention can improve the accuracy of the disconnection detection of the crankcase ventilation pipeline system.)

1. A pipeline disconnection detection method is applied to a pipeline disconnection detection system based on a conductive loop mechanism and used for detecting whether a crankcase ventilation pipeline system is disconnected or not, and is characterized in that the pipeline disconnection detection system comprises a disconnection detection circuit, and two ends of the disconnection detection circuit are respectively connected with a power supply end and a grounding end of an ECU unit; the disconnection detection circuit is provided with a resistance unit for diagnosing whether the disconnection detection circuit is short-circuited or not;

the pipeline disconnection detection method comprises the following steps:

detecting an electric signal of a point to be detected;

and judging whether the disconnection detection line is short-circuited or not according to the electric signal of the point to be detected.

2. The pipe disconnection detecting method according to claim 1, wherein the crankcase ventilation pipe system includes a main pipe to which a male connector connected to an engine crankcase or an intake system is connected, and a connection terminal is provided at an end of the main pipe;

the disconnection detection circuit is provided with a conductive switch, and the conductive switch is positioned inside the connecting terminal or at the joint of the male connector and the connecting terminal; when the male connector is connected with the connecting terminal, the conductive switch is conducted, so that the disconnection detection circuit and the ECU unit form a loop.

3. The pipe disconnection detecting method according to claim 1, wherein the ECU unit is provided with an upper resistor, which is located between the power source terminal and the resistor unit, to assist the disconnection detecting line in diagnosing a short circuit to ground; the point to be detected is one end of the disconnection detection circuit connected with the power supply end.

4. The pipeline disconnection detection method according to claim 3, wherein the electrical signal comprises a voltage signal, and the determining whether the disconnection detection line is short-circuited according to the electrical signal of the point to be detected comprises:

and if the voltage signal of the point to be detected corresponds to zero, judging that the disconnection detection line has a short circuit to the ground.

5. The method for detecting pipeline disconnection according to claim 4, wherein the step of determining whether the disconnection detection line is short-circuited according to the electrical signal of the point to be detected further comprises:

if the voltage signal of the point to be detected corresponds to the input voltage of the ECU unit, judging that the disconnection detection line is disconnected;

and if the voltage signal of the point to be detected corresponds to U × R _ pcv/(R _ ECU + R _ pcv), judging that the disconnection detection line works normally, wherein U is the input voltage of the ECU unit, R _ pcv is the resistance value of the resistance unit, and R _ ECU is the resistance value of the upper resistor.

6. The method of claim 3, wherein the upper resistor comprises a single resistor or a plurality of resistors; the plurality of resistors are connected in series or in parallel.

7. The pipe disconnection detection method according to claim 1, wherein the ECU unit is provided with a lower resistor between the ground terminal and the resistor unit to assist the disconnection detection line in diagnosing a power supply short circuit; the point to be detected is one end of the disconnection detection line connected with the grounding end.

8. The pipeline disconnection detection method according to claim 7, wherein the electrical signal comprises a voltage signal, and the determining whether the disconnection detection line is short-circuited according to the electrical signal of the point to be detected comprises:

and if the voltage signal of the point to be detected corresponds to the input voltage of the ECU unit, judging that the power supply is short-circuited by the disconnected detection line.

9. The method for detecting pipeline disconnection according to claim 8, wherein said determining whether the disconnection detection line is short-circuited according to the electrical signal of the point to be detected further comprises:

if the voltage signal of the point to be detected corresponds to zero, judging that the disconnection detection line is disconnected;

if the voltage signal of the point to be detected corresponds to U × R _ ecu '/(R _ ecu ' + R _ pcv '), then judging that the disconnection detection line works normally; wherein U is an input voltage of the ECU unit, R _ pcv 'is a resistance value of the resistance unit, and R _ ECU' is a resistance value of the lower resistor.

10. The conduit disconnection detection method of claim 7, wherein said lower resistor comprises a single resistor or a plurality of resistors; the plurality of resistors are connected in series or in parallel.

Technical Field

The invention relates to the field of automobile pipeline detection, in particular to a pipeline disconnection detection method.

Background

When the engine works, because of high pressure generated in the combustion chamber, the piston ring has a clearance or loses certain sealing effect, and the like, waste gas, unburned oil gas, carbon smoke particles, water vapor and the like in the combustion chamber can be communicated with a crankcase through the clearance between the piston and the cylinder wall.

At present, a closed crankcase ventilation system is mostly adopted for an engine, mainly to avoid that fuel oil components are volatilized into air to cause that evaporative emission of a whole vehicle exceeds standard, and to inhibit pressure rise in the crankcase, gas in the crankcase needs to be intermittently pumped out.

Vibration, high and low temperature change in the working process of an engine, material durability problems caused by long-term use and vehicle maintenance influence the integrity of a crankcase ventilation pipeline (such as pipe disconnection, joint disconnection and joint extraction).

The crankcase ventilation pipeline comprises a multi-section structure, such as a main pipeline, joints at two ends, or other connecting structures, and whether the main pipeline is disconnected or not and whether the joints at the two ends are pulled out or fall off or not need to be judged in online diagnosis. At present, in the existing scheme, a conductive wire (disconnection detection line) is arranged on a main pipeline, and whether a crankcase ventilation pipeline is disconnected or not is detected by detecting whether the conductive wire forms a loop or not.

However, the accuracy of the detection of the pipe disconnection detection system based on the conductive loop mechanism for the online diagnosis of pipe disconnection needs to be improved.

Disclosure of Invention

The inventor(s) found that, in some cases, for example, when the disconnection detection line is short-circuited (e.g., short-circuited to ground or short-circuited to power), even if the disconnection of the pipeline causes abnormal disconnection of the disconnection detection line, the current pipeline disconnection detection system based on the conductive loop mechanism cannot accurately diagnose.

Based on the detection, the invention provides a pipeline disconnection detection method which is applied to a pipeline disconnection detection system and used for detecting whether a crankcase ventilation pipeline system is disconnected or not, and meanwhile, a targeted design is made for the short circuit phenomenon possibly generated by disconnection of a detection circuit, so that the invention can effectively monitor whether the crankcase ventilation pipeline system has the falling phenomenon or not. The specific scheme is as follows:

the embodiment of the invention provides a pipeline disconnection detection method which is applied to a pipeline disconnection detection system based on a conductive loop mechanism and used for detecting whether a crankcase ventilation pipeline system is disconnected or not. The pipeline disconnection detection system comprises a disconnection detection line, and two ends of the disconnection detection line are respectively connected with a power supply end and a grounding end of the ECU unit; the disconnection detection circuit is provided with a resistance unit for diagnosing whether the disconnection detection circuit is short-circuited or not;

the pipeline disconnection detection method comprises the following steps:

detecting an electric signal of a point to be detected;

and judging whether the disconnection detection line is short-circuited or not according to the electric signal of the point to be detected.

In one embodiment, the crankcase ventilation pipeline system comprises a main pipeline, a male connector connected with an engine crankcase or an air inlet system is connected onto the main pipeline, and a connecting terminal is arranged at the end of the main pipeline;

the disconnection detection circuit is provided with a conductive switch, and the conductive switch is positioned inside the connecting terminal or at the joint of the male connector and the connecting terminal; when the male connector is connected with the connecting terminal, the conductive switch is conducted, so that the disconnection detection circuit and the ECU unit form a loop.

In one embodiment, the ECU unit is provided with an upper resistor, which is located between the power supply terminal and the resistor unit, to assist the disconnection detection line in diagnosing a short circuit to ground; the point to be detected is one end of the disconnection detection circuit connected with the power supply end.

In one embodiment, the determining whether the open detection line is short-circuited according to the electrical signal of the point to be detected includes:

and if the voltage signal of the point to be detected corresponds to zero, judging that the disconnection detection line has a short circuit to the ground.

In one embodiment, the determining whether the open detection line is short-circuited according to the electrical signal of the point to be detected further includes:

if the voltage signal of the point to be detected corresponds to the input voltage of the ECU unit, judging that the disconnection detection line is disconnected;

and if the voltage signal of the point to be detected corresponds to U × R _ pcv/(R _ ECU + R _ pcv), judging that the disconnection detection line works normally, wherein U is the input voltage of the ECU unit, R _ pcv is the resistance value of the resistance unit, and R _ ECU is the resistance value of the upper resistor.

In one embodiment, the upper resistance comprises a single resistance or a plurality of resistances; the plurality of resistors are connected in series or in parallel.

In one embodiment, the ECU unit is provided with a lower resistor located between the ground terminal and the resistor unit to assist the disconnection detection line in diagnosing a power supply short circuit; the point to be detected is one end of the disconnection detection line connected with the grounding end.

In one embodiment, the determining whether the open detection line is short-circuited according to the electrical signal of the point to be detected includes:

and if the voltage signal of the point to be detected corresponds to the input voltage of the ECU unit, judging that the power supply is short-circuited by the disconnected detection line.

In one embodiment, the determining whether the open detection line is short-circuited according to the electrical signal of the point to be detected further includes:

if the voltage signal of the point to be detected corresponds to zero, judging that the disconnection detection line is disconnected;

if the voltage signal of the point to be detected corresponds to U × R _ ecu '/(R _ ecu ' + R _ pcv '), then judging that the disconnection detection line works normally; wherein U is an input voltage of the ECU unit, R _ pcv 'is a resistance value of the resistance unit, and R _ ECU' is a resistance value of the lower resistor.

In one embodiment, the lower resistors comprise a single resistor or a plurality of resistors; the plurality of resistors are connected in series or in parallel.

Compared with the prior art, the embodiment has the following advantages:

the pipeline disconnection detection method provided by the invention can diagnose whether the disconnection detection line is short-circuited or not, and improve the accuracy of disconnection detection of the crankcase ventilation pipeline system.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

FIGS. 1-2 are schematic illustrations of the main line and the disconnect diagnostic line of the present invention with two different connection terminals;

FIG. 3 is a diagnostic schematic of the present invention, including more than two connection terminals, and in the case where the ECU unit is provided with an upper resistor;

FIG. 4 is a diagnostic schematic of the present invention including a connection terminal and having an upper resistor in the ECU unit;

FIG. 5 is a schematic diagram of the present invention with a lower resistor in the ECU unit;

FIG. 6 is a schematic diagram of a short circuit to ground in the case of an upper resistor according to the present invention;

FIG. 7 is a graph of voltage versus time for three conditions of the present invention when the ECU unit is provided with an upper resistor;

FIG. 8 is a schematic diagram of the present invention with a low resistor to short the power supply;

fig. 9 is a graph of voltage versus time for three cases when the ECU unit is provided with a low-level resistor in accordance with the present invention.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.

In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The following detailed description of the preferred embodiments of the invention, however, the invention is capable of other embodiments in addition to those detailed.

The invention designs a disconnection detection circuit capable of forming a current loop on a crankcase ventilation pipeline, which is used for monitoring whether a crankcase ventilation pipeline system (comprising a main pipeline and other pipelines connected with the main pipeline as optional items) has a shedding phenomenon or not. Wherein, include resistance unit and conducting switch in the disconnection detection circuitry, dispose other pipelines on the main pipeline after, the conducting switch on the disconnection detection circuitry switches on along with it to disconnection detection circuitry forms the return circuit: the current in the conductive loop passes through the power supply terminal of the ECU unit, the conductive switch (which may be plural) and then returns to the ground terminal of the ECU unit. Under the condition that a crankcase ventilation pipeline system is installed well, the circuit is conducted, if other pipelines fall off from a main pipeline or the middle of the main pipeline is completely disconnected, the conductive circuit is disconnected, and the ECU unit can rapidly detect faults. In addition, a resistance unit is arranged in the detection loop, so that the condition of power supply short circuit or ground short circuit of a wire harness connected with the ECU unit in a disconnection detection circuit is mainly diagnosed, and the disconnection detection accuracy of the crankcase ventilation pipeline system is further improved.

The specific scheme is as follows:

a pipeline disconnection detection system based on a conductive loop mechanism can be used for detecting whether a crankcase ventilation pipeline system is disconnected or not, the crankcase ventilation pipeline system comprises a main pipeline 1, a male connector connected with an engine crankcase or an air inlet system is connected to the main pipeline 1, and a connecting terminal is arranged on the main pipeline;

the pipeline disconnection detection system comprises a disconnection detection circuit fixed on a main pipeline 1 and at least one connecting terminal, wherein the connecting terminal is arranged on the main pipeline 1, a conductive switch is arranged on the disconnection detection circuit and is positioned inside the connecting terminal or at the joint of a male connector and the connecting terminal, the male connector is inserted into the connecting terminal or a male connector lock ring on the male connector is inserted into the connecting terminal, and the conductive switch can be conducted.

And two ends of the disconnection detection circuit are respectively connected with the power supply end and the grounding end of the ECU unit, and the disconnection detection circuit is provided with a resistor unit connected with the power supply end of the ECU unit and used for diagnosing the condition that the disconnection detection circuit generates a power supply short circuit or a ground short circuit.

In an optional embodiment of the present invention, the connection terminal is a quick-insertion female connector, and a conductive switch is disposed on the quick-insertion female connector, and the conductive switch inside the connection terminal is triggered to be turned on by the male connector when the male connector is inserted into the connection terminal. As shown in fig. 1, the connection terminal 6 has a quick-connect female connector, one end of the quick-connect female connector is disposed on the main pipe 1, the quick-plug male connector 3 can be inserted into the other end of the quick-connect female connector, and after the quick-plug male connector 3 is inserted into the connection terminal 6, the quick-plug male connector 3 can connect the conductive switch 2, thereby realizing the conduction of the disconnection detection line 10. When the disconnection detection circuit that the car was equipped with adopted the conductor wire among the current scheme, the joint at gas circuit both ends and the joint at conductor wire both ends are the separation, need connect well crankcase ventilation pipeline earlier when the installation, connect the conductor wire again and connect and realize switching on of disconnection detection circuit, install loaded down with trivial details. In the scheme provided by the invention, the conductive switch is arranged on the quick-insertion female connector, and after the quick-insertion male connector 3 is inserted into the quick-insertion female connector, the main pipeline can be connected with other pipelines, and meanwhile, the disconnected detection line is also conducted.

In an alternative embodiment of the present invention, as shown in fig. 2, the end of the main pipeline 1 is a flexible pipe and can be fastened to the male connector 8 by using a clamp 11, a circuit plug is arranged on the connection terminal 9 on the main pipeline 1, and a conductive structure is arranged in the male connector lock ring 5 on the male connector 8. When the main pipeline 1 is sleeved on the male connector 8, the circuit plug on the connecting terminal 9 is inserted into the male connector lock ring 5 on the male connector 8 in a proper manner, and the conductive switch is conducted by the conductive structure of the male connector lock ring, so that the conduction of the disconnected detection circuit is realized.

In another alternative embodiment, the resistance unit is used to implement an abnormal condition diagnosis in addition to the circuit on and off diagnosis, where the abnormal condition is a short circuit to the power supply or a short circuit to the ground occurring in the wire harness that opens the detection line 10.

In practical application, a conductive switch may be disposed on a connection terminal at one end of the main pipeline 1, or conductive switches may be disposed on connection terminals at two ends of the main pipeline 1, and when the conductive switches of the connection terminals at the two ends are both turned on, the detection circuit is disconnected to form a loop with the ECU unit. Furthermore, if three or more connection terminals can be provided on the main line 1, the present invention is also applicable, and the disconnection detection line and the ECU unit are ensured to form a loop by adding a corresponding number of conduction switches.

In an alternative embodiment of the present invention, referring to fig. 3, when an upper resistor is used in the ECU unit, the resistor unit R _ pcv on the disconnection detection line 10 enables the ECU unit to distinguish between a normal operating condition and an abnormal condition in which the positive electrode of the disconnection detection line 10 (i.e., the end of the disconnection detection line 10 connected to the power supply terminal of the ECU unit) is short-circuited to ground, where the upper resistor is a single or multiple resistors R _ ECU located inside the ECU unit between the power supply terminal of the ECU unit and the resistor unit R _ pcv. When a plurality of resistors are used as the upper resistors, the plurality of resistors included in the upper resistors may be connected in series or in parallel.

In an alternative embodiment of the present invention, referring to fig. 5, when the ECU unit employs the lower resistors, i.e., the single or multiple resistors R _ ECU 'located inside the ECU unit between the ground terminal of the ECU unit and the resistor unit R _ pcv, the resistor unit R _ pcv' on the disconnection detection line 10 allows the ECU unit to distinguish between a normal operation condition and an abnormal condition in which the negative terminal of the disconnection detection line 10 (i.e., the end of the disconnection detection line 10 connected to the ground terminal of the ECU unit) is short-circuited to the power supply. When a plurality of resistors are used as the lower resistors, the plurality of resistors included in the lower resistors may be connected in series or in parallel.

In an alternative embodiment of the present invention, the disconnection detecting line 10 is attached to the surface of the main line 1, and an insulating protective layer covers the main line 1 and the disconnection detecting line 10; or disconnection detection line 10 is buried in the material of main line 1 and led out at the end of the main line so that the metal portion of disconnection detection line 10 is not exposed. The conductive wires of the disconnection detection circuit 10 are tied together by the harness 4 and then connected to the ECU unit.

After connecting the connection terminals of the crankcase ventilation duct system and the main duct 1, the conductive switches are turned on by inserting the male connector, so that the disconnection detection circuit 10 and the ECU unit form a loop. When the male connector 3 is disengaged from the main pipe 1, the disconnection detection line is broken due to the absence of a trigger mechanism for turning on the conductive switch, and is detected by the ECU unit.

After connecting each connection terminal of the crankcase ventilation pipe system with the main pipe 1, by inserting the male connector, the circuit plug on the connection terminal 9 is inserted into the male connector lock ring 5, and each conductive switch is conducted, so that the disconnection detection circuit 10 forms a loop. When the male connector 8 is detached from the main pipe 1 or the main pipe 1 is pulled out from the male connector 8, the circuit plug on the connection terminal 9 is disengaged from the male connector lock ring, causing the disconnection detection line to be disconnected, and thus detected by the ECU unit.

Some current diagnostic systems employ conductive wires to diagnose a disconnection of the crankcase ventilation conduit system. As the usage time increases, the plastic skin on the outside of the conductive wire may wear, causing the metal wires inside to come into contact with other parts, which has some negative effects on the diagnosis. The pipeline disconnection detection system provided by the invention can improve the diagnosis accuracy. As will be described in detail below.