阅读说明：本技术 一种诊断方法及装置 (Diagnosis method and device ) 是由 肖姗姗 韩广华 王晋林 韩二龙 裴小雨 王正庭 于 2020-03-16 设计创作，主要内容包括：本发明提供了一种诊断方法及装置,应用于具有曲轴箱通风系统的车辆,曲轴箱通风系统包括与车辆的发动机连通的曲轴箱通风管,方法包括：在发动机处于高怠速的情况下,生成曲轴箱通风管发生泄漏的泄漏信号；对节气门开度和点火角度进行调整,确定发动机对应的闭环修正值；当闭环修正值达到最大限度,且发动机仍处于高怠速的情况下,生成曲轴箱通风管路的断开故障码。本发明可以使得车辆在每个驾驶循环中接收到此断开故障码时,报出该断开故障码并进行一次存储,可以满足相关法规中最小监测频率,并且可以减小车辆在使用过程中误报或者不报断开故障的问题。(The invention provides a diagnostic method and a diagnostic device, which are applied to a vehicle with a crankcase ventilation system, wherein the crankcase ventilation system comprises a crankcase ventilation pipe communicated with an engine of the vehicle, and the method comprises the following steps: generating a leak signal that a crankcase ventilation duct is leaking while the engine is at high idle; adjusting the opening degree and the ignition angle of a throttle valve, and determining a closed loop correction value corresponding to the engine; when the closed loop correction value reaches a maximum limit and the engine is still in a high idle speed condition, a disconnection fault code of the crankcase ventilation pipeline is generated. The invention can report the disconnection fault code and store the disconnection fault code once when the vehicle receives the disconnection fault code in each driving cycle, can meet the minimum monitoring frequency in related regulations, and can reduce the problem that the vehicle reports the disconnection fault in the using process or does not report the disconnection fault.)

1. A diagnostic method for use with a vehicle having a crankcase ventilation system including a crankcase ventilation duct in communication with an engine of the vehicle, the method comprising:

generating a leak signal that the crankcase ventilation duct is leaking while the engine is at high idle;

adjusting the opening degree and the ignition angle of a throttle valve, and determining a closed loop correction value corresponding to the engine;

generating a disconnection fault code for the crankcase ventilation circuit when the closed loop correction value reaches a maximum limit and the engine is still at the high idle speed.

2. The method of claim 1, wherein said adjusting throttle opening and firing angle to determine a corresponding closed-loop correction value for the engine comprises:

under the condition that the crankcase ventilation pipe is in a normal connection state and the mixed gas of the engine works under a preset air-fuel ratio, determining the oil injection time of an oil injector according to the preset air-fuel ratio;

adjusting the fuel injection quantity through an oxygen sensor signal according to the fuel injection time of the fuel injector;

controlling the amount of gas entering the engine through the opening of a throttle valve, and determining a fuel self-learning value;

and adjusting the opening of a throttle valve and the pull-down ignition angle to a small value through the fuel oil self-learning value, and determining a closed loop correction value corresponding to the engine.

3. The method of claim 1, wherein prior to generating a leak signal that the crankcase ventilation duct is leaking while the engine is at high idle, the method further comprises:

and under the condition that the engine moves within a preset rotating speed range, adjusting the opening of the throttle valve according to the preset rotating speed to control the air inflow.

4. The method of claim 1, wherein generating a disconnection fault code for the crankcase ventilation circuit when the closed-loop modifier reaches a maximum limit and the engine is still at the high idle speed comprises:

when the closed-loop correction value reaches the maximum limit and the air intake quantity of the engine is increased, acquiring the rotating speed of the engine;

determining that the rotating speed of the engine is greater than the maximum rotating speed corresponding to a preset rotating speed range;

generating an open fault code for the crankcase ventilation line.

5. The method of claim 1, wherein the crankcase ventilation system further comprises:

an intake manifold and a positive crankcase ventilation valve interconnected with the crankcase ventilation duct;

the generating a leak signal that the crankcase ventilation duct is leaking while the engine is at high idle speed includes:

determining that the engine is in the high idle state with the positive crankcase ventilation valve and/or the intake manifold interface disconnected;

generating the leak signal that the crankcase ventilation duct is leaking based on the engine being in the high idle state.

6. A diagnostic device for use with a vehicle having a crankcase ventilation system including a crankcase ventilation duct in communication with an engine of the vehicle, the device comprising:

the first generation module is used for generating a leakage signal that the crankcase ventilation pipe leaks when the engine is in a high idling state;

the determining module is used for adjusting the opening degree and the ignition angle of a throttle valve and determining a closed loop correction value corresponding to the engine;

a second generating module configured to generate a disconnection fault code for the crankcase ventilation circuit when the closed-loop correction value reaches a maximum limit and the engine is still at the high idle speed.

7. The apparatus of claim 6, wherein the determining module comprises:

the first determining submodule is used for determining the oil injection time of an oil injector according to a preset air-fuel ratio under the condition that the crankcase ventilation pipe is in a normal connection state and the air-fuel mixture of the engine works under the preset air-fuel ratio;

the adjusting submodule is used for adjusting the oil injection quantity through an oxygen sensor signal according to the oil injection time of the oil injector;

the second determining submodule is used for controlling the amount of gas entering the engine through the opening degree of a throttle valve and determining a fuel self-learning value;

and the third determining submodule is used for adjusting the opening of a throttle valve and the pull-down ignition angle to be small through the fuel oil self-learning value and determining a closed loop correction value corresponding to the engine.

8. The apparatus of claim 6, further comprising:

and the adjusting module is used for adjusting the opening of the throttle valve according to the preset rotating speed to control the air inflow under the condition that the engine moves within the preset rotating speed range.

9. The apparatus of claim 6, wherein the second generating module comprises:

the obtaining submodule is used for obtaining the rotating speed of the engine under the condition that the closed-loop correction value reaches the maximum limit and the air intake quantity of the engine is increased;

the fourth determining submodule is used for determining that the rotating speed of the engine is greater than the maximum rotating speed corresponding to the preset rotating speed range;

a first generation submodule to generate an open fault code for the crankcase ventilation circuit.

10. The method of claim 6, wherein the crankcase ventilation system further comprises:

an intake manifold and a positive crankcase ventilation valve interconnected with the crankcase ventilation duct;

the first generation module comprises:

a fifth determination submodule for determining that the engine is in the high idle state if the positive crankcase ventilation valve and/or the interface of the intake manifold is disconnected;

a second generating submodule configured to generate the leak signal that the crankcase ventilation duct leaks based on the engine being in the high idle state.

Technical Field

The invention relates to the technical field of vehicle control, in particular to a diagnosis method and a diagnosis device.

Background

With the gradual development of the technical field of vehicle control, vehicle pollutant limits are tightened for light automobiles (vehicles of the M1, M2 and N1 classes with the maximum total mass not exceeding 3.5 t). Regulations require that light duty vehicles use Positive Crankcase Ventilation (PCV) valve systems and that PCV valve systems should be monitored to ensure system integrity, that vehicle malfunction indicators light up after any interface of the system is disconnected, and that fault codes are stored.

PCV valve systems include valves or orifices for controlling or limiting crankcase ventilation, as well as all forms of external piping and hoses for ventilating or balancing crankcase pressure. The phenomenon that each interface of an engine of a vehicle is not installed or falls off in the maintenance and operation processes, a driver cannot sense that the connection of a crankcase ventilation pipe is abnormal, and the blow-by gas of the crankcase is directly discharged into the atmosphere to cause environmental pollution.

Currently, there are some diagnostic methods for opening crankcase ventilation systems, such as monitoring engine crankcase pressure, conducting line methods, fuel system lean burn methods, etc. And, throughout the vehicle operating cycle, it is necessary to monitor the PCV valve system and store fault codes.

In the existing diagnosis scheme, a small part of vehicles are provided with a Heat Flow Meter (HFM), and the fuel system lean combustion method requires the pipeline diameter to be oversized, so that the engine is difficult to arrange; the matching problem of circuit part structure design of the conductive pipeline method and the production and manufacturing problems of the parts can cause the false reporting or failure code reporting of the engine; the method for monitoring the pressure of the crankcase of the engine works by utilizing the pressure sensor, the precision of the sensor is low, the pressure of the crankcase in the disconnection and connection states of the ventilation pipeline is not obviously changed, and multiple false alarm fault codes can exist.

Disclosure of Invention

In view of the above, the present invention is directed to a diagnostic method and apparatus for solving the problem of multiple false alarm of fault codes in the existing diagnostic method.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

in a first aspect, an embodiment of the present invention provides a diagnostic method for a vehicle having a crankcase ventilation system including a crankcase ventilation duct in communication with an engine of the vehicle, the method including:

generating a leak signal that the crankcase ventilation duct is leaking while the engine is at high idle;

adjusting the opening degree and the ignition angle of a throttle valve, and determining a closed loop correction value corresponding to the engine;

generating a disconnection fault code for the crankcase ventilation circuit when the closed loop correction value reaches a maximum limit and the engine is still at the high idle speed.

Optionally, the adjusting the throttle opening and the ignition angle to determine a corresponding closed-loop correction value of the engine includes:

under the condition that the crankcase ventilation pipe is in a normal connection state and the mixed gas of the engine works under a preset air-fuel ratio, determining the oil injection time of an oil injector according to the preset air-fuel ratio;

adjusting the fuel injection quantity through an oxygen sensor signal according to the fuel injection time of the fuel injector;

controlling the amount of gas entering the engine through the opening of a throttle valve, and determining a fuel self-learning value;

and adjusting the opening of a throttle valve and the pull-down ignition angle to a small value through the fuel oil self-learning value, and determining a closed loop correction value corresponding to the engine.

Optionally, before generating a leak signal that the crankcase ventilation duct leaks while the engine is at high idle speed, the method further comprises:

and under the condition that the engine moves within a preset rotating speed range, adjusting the opening of the throttle valve according to the preset rotating speed to control the air inflow.

Optionally, generating a disconnection fault code for the crankcase ventilation circuit when the closed loop correction value reaches a maximum limit and the engine is still at the high idle speed comprises:

when the closed-loop correction value reaches the maximum limit and the air intake quantity of the engine is increased, acquiring the rotating speed of the engine;

determining that the rotating speed of the engine is greater than the maximum rotating speed corresponding to a preset rotating speed range;

generating an open fault code for the crankcase ventilation line.

Optionally, the crankcase ventilation system further comprises:

an intake manifold and a positive crankcase ventilation valve interconnected with the crankcase ventilation duct;

the generating a leak signal that the crankcase ventilation duct is leaking while the engine is at high idle speed includes:

determining that the engine is in the high idle state with the positive crankcase ventilation valve and/or the intake manifold interface disconnected;

generating the leak signal that the crankcase ventilation duct is leaking based on the engine being in the high idle state.

In a second aspect, an embodiment of the present invention provides a diagnostic device for use with a vehicle having a crankcase ventilation system including a crankcase ventilation duct in communication with an engine of the vehicle, the device comprising:

the first generation module is used for generating a leakage signal that the crankcase ventilation pipe leaks when the engine is in a high idling state;

the determining module is used for adjusting the opening degree and the ignition angle of a throttle valve and determining a closed loop correction value corresponding to the engine;

a second generating module configured to generate a disconnection fault code for the crankcase ventilation circuit when the closed-loop correction value reaches a maximum limit and the engine is still at the high idle speed.

Optionally, the determining module includes:

the first determining submodule is used for determining the oil injection time of an oil injector according to a preset air-fuel ratio under the condition that the crankcase ventilation pipe is in a normal connection state and the air-fuel mixture of the engine works under the preset air-fuel ratio;

the adjusting submodule is used for adjusting the oil injection quantity through an oxygen sensor signal according to the oil injection time of the oil injector;

the second determining submodule is used for controlling the amount of gas entering the engine through the opening degree of a throttle valve and determining a fuel self-learning value;

and the third determining submodule is used for adjusting the opening of a throttle valve and the pull-down ignition angle to be small through the fuel oil self-learning value and determining a closed loop correction value corresponding to the engine.

Optionally, the apparatus further comprises:

and the adjusting module is used for adjusting the opening of the throttle valve according to the preset rotating speed to control the air inflow under the condition that the engine moves within the preset rotating speed range.

Optionally, the second generating module includes:

the obtaining submodule is used for obtaining the rotating speed of the engine under the condition that the closed-loop correction value reaches the maximum limit and the air intake quantity of the engine is increased;

the fourth determining submodule is used for determining that the rotating speed of the engine is greater than the maximum rotating speed corresponding to the preset rotating speed range;

a first generation submodule to generate an open fault code for the crankcase ventilation circuit.

Optionally, the crankcase ventilation system further comprises:

an intake manifold and a positive crankcase ventilation valve interconnected with the crankcase ventilation duct;

the first generation module comprises:

a fifth determination submodule for determining that the engine is in the high idle state if the positive crankcase ventilation valve and/or the interface of the intake manifold is disconnected;

a second generating submodule configured to generate the leak signal that the crankcase ventilation duct leaks based on the engine being in the high idle state.

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

according to the diagnosis method provided by the embodiment of the invention, under the condition that the engine is in a high idle speed, a leakage signal of the crankcase ventilation pipe leakage is generated, the opening degree and the ignition angle of the throttle valve are adjusted, a closed loop correction value corresponding to the engine is determined, and when the closed loop correction value reaches the maximum limit and the engine is still in the high idle speed, a disconnection fault code of the crankcase ventilation pipe is generated, so that the vehicle receives the disconnection fault code in each driving cycle, reports the disconnection fault code and stores the disconnection fault code once, the minimum monitoring frequency in relevant regulations can be met, and the problem that the vehicle reports the wrong disconnection fault or does not report the disconnection fault in the use process can be reduced.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a flow chart illustrating the steps of a diagnostic method according to an embodiment of the present invention;

FIG. 2 illustrates a schematic view of a crankcase ventilation duct arrangement provided by an embodiment of the present invention;

FIG. 3 is a flow chart illustrating the steps of a diagnostic method according to a second embodiment of the present invention;

FIG. 4 illustrates a schematic of an air-fuel ratio control strategy provided by an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a diagnostic apparatus according to a third embodiment of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

Referring to FIG. 1, a flow chart illustrating steps of a diagnostic method provided by an embodiment of the present invention may be applied to a vehicle having a crankcase ventilation system including a crankcase ventilation tube in communication with an engine of the vehicle.

As shown in fig. 1, the diagnostic method may specifically include the following steps:

step 101: a leak signal is generated that a crankcase ventilation duct is leaking while the engine is at high idle.

In an embodiment of the invention, crankcase ventilation system monitoring requires all manner of crankcase ventilation systems, including positive pressure ventilation systems, including all types of valves or ports for controlling or limiting crankcase ventilation, all types of external conduits and hoses for ventilating or balancing crankcase pressure, wherein upon disconnection of any one of the ports, a vehicle fault indicator is illuminated and a fault code is stored.

Fig. 2 shows a schematic diagram of a crankcase ventilation duct arrangement according to an embodiment of the invention, and as shown in fig. 2, the crankcase ventilation system may include: crankcase ventilation pipe 01, cylinder head cover 02, intake manifold 03, Positive Crankcase Ventilation (PCV) valve 04, clamp one 05, clamp two 06, and Electronic Control Unit (ECU) 07. One end of the crankcase ventilation pipe 01 is connected with a connector 031 of the intake manifold 03, the other end of the crankcase ventilation pipe is connected with an air outlet pipe 041 of the PCV valve 04, and the connector 031 and the air outlet pipe 041 are fastened through a first clamp 05 and a second clamp 06. Under the condition that the engine is in an idling state, air inlet directly sucks blow-by gas from a crankcase, the PCV 04 adjusts the blow-by gas flow of the crankcase according to different negative pressures of the air inlet manifold 03, the pressure of the crankcase is further adjusted to meet design requirements, and the speed of the vehicle is in a normal range after the vehicle is started in a normal connection state.

It should be noted that, in the process of maintenance and operation of the engine, the two ends of the rubber tube are connected to the air outlet tube 041 of the PCV valve 04 and the interface 031 of the intake manifold 03 through the first clamp 05 and the second clamp 06, which is not installed or falls off, that is, any interface of the pipeline is disconnected, the intake manifold 03 directly sucks the atmosphere through the interface of the disconnected pipeline, the air outlet tube 041 of the PCV valve 04 is also directly communicated with the atmosphere, the blow-by gas of the crankcase leaks through the interface and pollutes the air, and the disconnection fault should be diagnosed and the fault code is stored when the fault code occurs.

In the embodiment of the invention, when an air inlet pipeline has no leakage, air enters an engine through an air filtering system, the air inflow of each working condition of the engine is set through calibration, the air inflow is controlled by adjusting the opening degree of a throttle valve 08 according to a preset rotating speed, after any interface of a crankcase ventilation pipe 01 is disconnected, an air inlet manifold 03 does not absorb crankcase blowby gas, but directly sucks air through the disconnected interface, the air does not carry out flow regulation through a PCV (positive pressure control) valve 04, at the moment, an air inlet channel of the engine comprises the throttle valve 08 and the disconnected interface, when the inner diameter of the disconnected interface is at least 8 mm, the air inflow is rapidly increased, the rotating speed of the idling working condition of the engine rises and is higher than the preset rotating speed at the calibration, the high idling can be judged according to the different pipe diameters of the crankcase ventilation pipe and the normal idling speed of 1.5-2 times per minute is generally higher than 200 per minute, and the idling rises to a certain specific value in the range for stabilization, and at the moment, the engine is in a high idling state instead of idling fluctuation and other problems, so that the leakage of the crankcase ventilation pipe is judged, and a leakage signal of the crankcase ventilation pipe is generated when the idle fluctuation is not caused by other reasons.

Step 102 is performed after a leak signal is generated that a crankcase ventilation duct is leaking while the engine is at high idle.

Step 102: and adjusting the opening degree and the ignition angle of the throttle valve to determine a closed loop correction value corresponding to the engine.

After a leakage signal indicating that the crankcase ventilation pipe leaks is generated, the leakage signal can be sent to the ECU 07, and the ECU 07 receives the leakage signal, starts to continuously reduce and adjust the opening of the throttle valve 08, pulls down the ignition angle, and determines a closed loop correction value of the engine.

After the throttle opening and the ignition angle are adjusted to determine the closed-loop correction value corresponding to the engine, step 103 is executed.

Step 103: when the closed loop correction value reaches a maximum limit and the engine is still in a high idle speed condition, a disconnection fault code of the crankcase ventilation pipeline is generated.

When the closed loop correction value reaches the maximum limit, namely when the adjusting capacity reaches the maximum limit, the air quantity entering the engine from the leakage hole is still large, the oil injection quantity is increased along with the air-fuel ratio control strategy of the gasoline engine, so that the work is increased, the rotating speed of the engine is further increased, and at the moment, the ECU 07 writes a set disconnection fault code to indicate that a crankcase ventilation pipe disconnection signal is received.

After a disconnection fault code for the crankcase ventilation circuit is generated when the closed loop correction value is maximized and the engine is still at high idle, step 104 is performed.

After the disconnection fault code of the crankcase ventilation pipeline is generated, the ECU 07 receives the disconnection fault code in each driving cycle of the vehicle, reports the disconnection fault code and stores the disconnection fault code once, and the vehicle needs to be diagnosed in the whole operation period, so that the minimum monitoring frequency in the regulation can be met.

According to the diagnosis method provided by the embodiment of the invention, under the condition that the engine is in a high idle speed, a leakage signal of the crankcase ventilation pipe leakage is generated, the opening degree and the ignition angle of the throttle valve are adjusted, a closed loop correction value corresponding to the engine is determined, and when the closed loop correction value reaches the maximum limit and the engine is still in the high idle speed, a disconnection fault code of the crankcase ventilation pipe is generated, so that the vehicle receives the disconnection fault code in each driving cycle, reports the disconnection fault code and stores the disconnection fault code once, the minimum monitoring frequency in relevant regulations can be met, and the problem that the vehicle reports the disconnection fault in the use process or does not report the disconnection fault can be reduced.

Referring to FIG. 3, a flowchart illustrating steps of a diagnostic method according to a second embodiment of the present invention is provided for use with a vehicle having a crankcase ventilation system including a crankcase ventilation tube in communication with an engine of the vehicle.

As shown in fig. 3, the diagnostic method may specifically include the following steps:

step 201: and under the condition that the engine moves within the preset rotating speed range, adjusting the opening of a throttle valve according to the preset rotating speed to control the air inflow.

In the embodiment of the invention, when the air inlet pipeline has no leakage, air is filtered by the air filter system and enters the engine, the air inflow of each working condition of the engine is set by calibration, and the opening of the throttle valve 08 is adjusted according to the preset rotating speed to control the air inflow.

After the throttle opening is adjusted according to the preset rotation speed to control the intake air amount in the case where the engine is moving within the preset rotation speed range, step 202 is performed.

Step 202: a leak signal is generated that a crankcase ventilation duct is leaking while the engine is at high idle.

Fig. 2 shows a schematic diagram of a crankcase ventilation duct arrangement according to an embodiment of the present invention, as shown in fig. 2, including: crankcase ventilation pipe 01, cylinder head cover 02, intake manifold 03, Positive Crankcase Ventilation (PCV) valve 04, clamp one 05, clamp two 06, and Electronic Control Unit (ECU) 07. One end of the crankcase ventilation pipe 01 is connected with a connector 031 of the intake manifold 03, the other end of the crankcase ventilation pipe is connected with an air outlet pipe 041 of the PCV valve 04, and the connector 031 and the air outlet pipe 041 are fastened through a first clamp 05 and a second clamp 06. Under the condition that the engine is in an idling state, the air intake manifold 03 directly sucks blow-by gas from the crankcase, the PCV valve 04 adjusts the blow-by gas flow of the crankcase according to different negative pressures of the air intake manifold 03, the pressure of the crankcase is further adjusted to meet design requirements, and the speed of the vehicle is in a normal range after the vehicle is started in a normal connection state.

Implementations of step 202 may include: determining that the engine is in a high idle state in the event that the interface of the positive crankcase ventilation valve and/or the intake manifold is disconnected; a leak signal is generated that a crankcase ventilation duct is leaking based on the engine being in a high idle state.

Specifically, when the air inlet pipeline has no leakage, air enters the engine through the air filtering system, the air inflow of each working condition of the engine is set through calibration, the air inflow is controlled by adjusting the opening degree of the throttle valve 08 according to the preset rotating speed, after any interface of the crankcase ventilation pipe 01 is disconnected, the air intake manifold 03 does not absorb the blow-by gas of the crankcase, the air is directly sucked through the disconnected interface, the air does not carry out flow regulation through the PCV valve 04, at the moment, the air inlet channel of the engine comprises the throttle valve 08 and the disconnected interface, when the inner diameter of the disconnected interface is at least 8 mm, the air inflow is rapidly increased, the rotating speed of the idling working condition of the engine rises and is higher than the preset rotating speed when the rotating speed is higher than the calibration, the idling can be judged to be high according to the different pipe diameters of the crankcase ventilation pipe, the normal idling speed is generally higher than 200 per minute, and the idling rises to a certain specific value in the range for stabilization, and at the moment, the engine is in a high idling state instead of idling fluctuation and other problems, so that the leakage of the crankcase ventilation pipe is judged, and a leakage signal of the crankcase ventilation pipe is generated when the idle fluctuation is not caused by other reasons.

It should be noted that, in the process of maintenance and operation of the engine, two ends of the rubber tube are connected with the air outlet tube 041 of the PCV valve 04 and the interface 031 of the intake manifold 03 through the first clamp 05 and the second clamp 06, and there is a phenomenon that the rubber tube is not installed or falls off, that is, any interface of the pipeline is disconnected, the intake manifold 03 directly sucks atmosphere through the interface of the disconnected pipeline, the air outlet tube 041 of the PCV valve 04 is also directly communicated with atmosphere, blow-by gas of the crankcase can leak through the air outlet tube 041 and pollute the air, and if the fault code occurs, a disconnection fault should be diagnosed and the fault code is stored.

After a leak signal is generated that a crankcase ventilation line is leaking while the engine is at high idle, step 203 is executed.

Step 203: and adjusting the opening degree and the ignition angle of the throttle valve to determine a closed loop correction value corresponding to the engine.

After a leakage signal of the crankcase ventilation pipe leakage is generated, the leakage signal is sent to the ECU 07, the ECU receives the leakage signal, the opening of the throttle valve 08 is adjusted to be small and small continuously, the ignition angle is pulled down, and a closed loop correction value of the engine is determined.

The specific implementation of step 203 may include: determining the oil injection time of an oil injector according to a preset air-fuel ratio under the condition that a crankcase ventilation pipe is in a normal connection state and the mixed gas of an engine works under the preset air-fuel ratio; adjusting the fuel injection quantity through an oxygen sensor signal according to the fuel injection time of the fuel injector; controlling the amount of gas entering an engine through the opening degree of a throttle valve, and determining a fuel self-learning value; and (4) adjusting the opening of a throttle valve and the pull-down ignition angle to a small value through the fuel oil self-learning value, and determining a corresponding closed-loop correction value of the engine.

Specifically, referring to fig. 4, the crankcase ventilation pipe 01 is in a normal connection state, when the mixture of the engine works under a theoretical air-fuel ratio of 14.6, in the electronic injection control system of the engine, the air-fuel ratio (A/F) is controlled by calculating the air inlet quantity (M) of the engine through an air inlet sensor_air) Then, an Engine Control Module (ECM) calculates an injection time t of a basic injection amount corresponding to an intake air amount based on an air-fuel ratio Control target_iFinally, the fuel injection quantity is adjusted in real time through the signal feedback of the oxygen sensor, finally the quantity of gas entering the engine is controlled through the opening degree of a throttle valve 08, the condition that the air-fuel ratio of the mixed gas is close to the theoretical air-fuel ratio to achieve the expected idle speed control is met, and the fuel self-learning value (K) is obtained_xx)。

In addition, the accurate injection of fuel is accomplished through the high-pressure injection system, and the oil mass of sprayer is:

wherein M is_fuelRepresenting the fuel injection quantity quality of the fuel injector; ρ represents the gasoline density; q represents the volume of fuel injected by the fuel injection nozzle; k represents an oil injection characteristic factor of the oil injector; s represents the effective oil injection cross-sectional area of the oil injection nozzle; DP represents the pressure difference between two sides of the oil injection port of the oil injector; t is t_iRepresenting the oil injection pilot injection pulse width; k_xxAnd showing the self-learning value of the fuel.

The fuel oil system carries out closed-loop control according to the oxygen sensing signal and carries out closed-loop control according to the fuel oil self-learning value K_xxCorrecting the oil injection:

after the throttle opening and the ignition angle are adjusted to determine the closed-loop correction value corresponding to the engine, step 204 is performed.

Step 204: when the closed loop correction value reaches a maximum limit and the engine is still in a high idle speed condition, a disconnection fault code of the crankcase ventilation pipeline is generated.

The specific implementation process of step 204 may include:

when the closed-loop correction value reaches the maximum limit and the air intake amount of the engine is increased, acquiring the rotating speed of the engine; determining that the rotating speed of the engine is greater than the maximum rotating speed corresponding to the preset rotating speed range; an open fault code for the crankcase ventilation line is generated.

Specifically, when the closed-loop correction value reaches the maximum limit, that is, when the adjustment capacity reaches the maximum limit, the amount of air entering the engine from the leakage hole is still large, the amount of injected oil is increased accordingly based on the air-fuel ratio control strategy of the gasoline engine, so that the work is increased, the rotating speed of the engine is further increased, and at the moment, the ECU 07 writes a set disconnection fault code to indicate that a crankcase ventilation pipe disconnection signal is received.

After a disconnection fault code for the crankcase ventilation circuit is generated when the closed loop correction value is at a maximum and the engine is still at high idle, step 205 is performed.

After the disconnection fault code of the crankcase ventilation pipeline is generated, the ECU 07 receives the disconnection fault code in each driving cycle of the vehicle, reports the disconnection fault code and stores the disconnection fault code once, and the vehicle needs to be diagnosed in the whole operation period, so that the minimum monitoring frequency in the regulation can be met.

When the crankcase ventilation pipe is not assembled or falls off, the idling speed of the vehicle is obviously increased after the vehicle is started, and the ECU diagnoses a disconnection fault; the invention can utilize the existing pipeline to realize disconnection diagnosis of faults by an engine air-fuel ratio control strategy, and successfully solves the problem that the vehicle misrereports or does not report the disconnection fault code of a crankcase ventilation system in the use process due to the aging of a conductive pipeline, the quality of a sample piece, the precision of a crankcase pressure sensor and the like; the ventilation pipeline is designed for the size of a conventional pipeline, so that the cost of HFM (high frequency modulation) of the hollow filter system in the fuel system lean combustion diagnosis method is saved, the problems of thickening the pipeline and realizing diagnosis by the size of a connector are solved, the pipeline arrangement of an engine is more convenient, and the space of an engine room is saved.

According to the diagnosis method provided by the embodiment of the invention, under the condition that the engine moves within the preset rotating speed range, the opening of the throttle valve is adjusted according to the preset rotating speed to control the air inflow, under the condition that the engine is in a high idle speed, a leakage signal of leakage of a crankcase ventilation pipe is generated, the opening of the throttle valve and the ignition angle are adjusted, a closed loop correction value corresponding to the engine is determined, and when the closed loop correction value reaches the maximum limit and the engine is still in the high idle speed, a disconnection fault code of the crankcase ventilation pipe is generated, so that the vehicle receives the disconnection fault code in each driving cycle, reports the disconnection fault code and stores the disconnection fault code once, the minimum monitoring frequency in relevant regulations can be met, and the problem that the vehicle misreports or does not report the disconnection fault in the use process can be reduced.

Referring to fig. 5, a schematic structural diagram of a diagnostic apparatus provided in a third embodiment of the present invention is shown, the diagnostic apparatus being applied to a vehicle having a crankcase ventilation system including a crankcase ventilation duct communicating with an engine of the vehicle.

As shown in fig. 5, the diagnostic apparatus 300 may specifically include:

a first generating module 301, configured to generate a leakage signal indicating that a crankcase ventilation duct is leaking when the engine is at a high idle speed;

the determining module 302 is used for adjusting the opening degree and the ignition angle of a throttle valve and determining a closed loop correction value corresponding to the engine;

a second generating module 303, configured to generate a disconnection fault code of the crankcase ventilation pipeline when the closed-loop correction value reaches a maximum limit and the engine is still in a high idle speed;

optionally, the determining module includes:

the first determining submodule is used for determining the oil injection time of the oil injector according to a preset air-fuel ratio under the condition that a crankcase ventilation pipe is in a normal connection state and the mixed gas of the engine works under the preset air-fuel ratio;

the adjusting submodule is used for adjusting the oil injection quantity through an oxygen sensor signal according to the oil injection time of the oil injector;

the second determining submodule is used for controlling the amount of gas entering the engine through the opening degree of a throttle valve and determining a fuel self-learning value;

and the third determining submodule is used for adjusting the opening of the throttle valve and the pull-down ignition angle to be small through the fuel oil self-learning value and determining a closed loop correction value corresponding to the engine.

Optionally, the apparatus further comprises:

and the adjusting module is used for adjusting the opening of the throttle valve according to the preset rotating speed to control the air inflow under the condition that the engine moves within the preset rotating speed range.

Optionally, the second generating module includes:

the acquisition submodule is used for acquiring the rotating speed of the engine under the condition that the closed-loop correction value reaches the maximum limit and the air intake quantity of the engine is increased;

the fourth determining submodule is used for determining that the rotating speed of the engine is greater than the maximum rotating speed corresponding to the preset rotating speed range;

a first generating submodule for generating an open fault code for the crankcase ventilation circuit.

Optionally, the crankcase ventilation system further comprises:

an intake manifold and a positive crankcase ventilation valve interconnected with the crankcase ventilation duct;

the first generation module comprises:

a fifth determination submodule for determining that the engine is in a high idle state in the event that the interface of the positive crankcase ventilation valve and/or the intake manifold is disconnected;

and the second generation submodule is used for generating a leakage signal of the crankcase ventilation pipe leakage based on the engine in a high idling state.

The specific implementation of the diagnostic apparatus in the embodiment of the present invention has been described in detail on the method side, and therefore, the detailed description thereof is omitted here.

According to the diagnosis method provided by the embodiment of the invention, the first generation module is used for generating a leakage signal of the crankcase ventilation pipe leakage under the condition that the engine is in a high idle speed, the determination module is used for adjusting the opening degree and the ignition angle of the throttle valve and determining the closed loop correction value corresponding to the engine, and the second generation module is used for generating the disconnection fault code of the crankcase ventilation pipe under the condition that the closed loop correction value reaches the maximum limit and the engine is still in the high idle speed, so that the vehicle receives the disconnection fault code in each driving cycle, reports the disconnection fault code and stores the disconnection fault code once, the minimum monitoring frequency in relevant regulations can be met, and the problem that the vehicle misrereports or does not report the disconnection fault in the use process can be reduced.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.