CN107678419B

CN107678419B - Intelligent VGT actuator active responsiveness diagnosis method

Info

Publication number: CN107678419B
Application number: CN201710888344.4A
Authority: CN
Inventors: 陈铁; 任灵童; 吕颖
Original assignee: FAW Group Corp
Current assignee: FAW Group Corp
Priority date: 2017-09-27
Filing date: 2017-09-27
Publication date: 2020-03-17
Anticipated expiration: 2037-09-27
Also published as: CN107678419A

Abstract

The invention discloses an active responsiveness diagnosis method for an intelligent VGT actuator. According to the method for diagnosing the active responsiveness of the intelligent VGT actuator, firstly, the condition of an EGR valve, the working condition of an engine, the external environment and the state of a related actuator are judged, the condition that other interference exists in a closed loop space of a diagnosis function is eliminated, the judgment of the diagnosis function is influenced, an excitation signal is transmitted to the VGT actuator through the ECU, the VGT actuator can normally feed back a related control value after receiving the signal, and the ECU calculates the amplitude of the received signal according to Fourier transform after receiving the related feedback signal. And comparing the calculated value with the inherent threshold value to confirm and output the fault.

Description

Intelligent VGT actuator active responsiveness diagnosis method

Technical Field

The invention belongs to the field of electronic control of automobile engines, and relates to a diagnosis method for diagnosing the responsiveness of an actuator by actively exciting the actuator and judging the effect of resonance generation based on Fourier transform.

Background

With the continuous increase of environmental awareness worldwide, vehicle emission regulations are becoming stricter. At present, China has started to implement the national IV emission regulations on a large scale, and the national V emission regulations are started to implement in developed areas such as Beijing and Shanghai. In the future, about 2020, national VI emission regulations will be implemented. Legislation will put forward a clear demand on the response performance of actuators affecting emissions, and it is necessary to make a judgment on faults such as actuator sticking, carbon deposition, etc.

In a new generation of diesel engine structures that meet the emission legislation in state vi, VGTs (variable cross-sectional area turbochargers) will become the standard configuration for engines. And actuators such as EGR (exhaust gas recirculation) and a throttle valve in a gas circuit system are matched for coupling control, so that combustion of the diesel engine is improved, exhaust temperature is controlled, and emission is optimized. When the response performance of the VGT actuator is reduced, the management strategy of the gas circuit is obviously and negatively influenced, and finally, combustion deterioration and excessive emission are caused.

In the traditional actuator responsiveness diagnosis, after the diagnosis condition is met, the current gas flow is compared with the threshold flow value calibrated under the working condition for judgment. The method needs calibration work of a large amount of data, and reliability and accuracy cannot be guaranteed. Erroneous judgment is easily generated.

Disclosure of Invention

The invention aims to provide an intelligent VGT actuator active responsiveness diagnosis method aiming at the difficulty of traditional actuator responsiveness diagnosis, which is based on Fourier transform, actively excites an actuator to generate a resonance waveform and judges the actuator responsiveness state by comparing the attenuation degree of the waveform.

The technical scheme adopted by the invention for solving the technical problems is as follows: an intelligent VGT actuator active responsiveness diagnostic method, comprising:

s10, judging whether the EGR valve reaches the admission working condition or not according to the comparison result of the change of the set system flow and the set threshold value;

s20, the engine temperature, the ambient temperature, the EGR valve position, the throttle position and the supercharging control mode meet the operation conditions;

s30, calculating the diagnosis time t and the diagnosis success cycle number;

s40, transmitting a sine signal of sin (2 pi tf) to the VGT actuator through the ECU, wherein f is the transmitting frequency;

and S50, receiving a feedback signal r of the VGT actuator through the ECU.

S60, obtained by changing the function S (t) according to the first-order fourier transform function (t) acos (2 pi tf) + bsin (2 pi tf):

by the formula

Calculating a corresponding system amplitude omega;

and S70, comparing the amplitude threshold value with the calculated amplitude omega after necessary correction is carried out on the amplitude threshold value through the atmospheric pressure and the ambient temperature, and if the calculated amplitude is smaller than the threshold value, then the VGT has a response fault and the diagnosis is successful once.

The invention has the following beneficial effects: according to the method for diagnosing the active responsiveness of the intelligent VGT actuator, firstly, the condition of an EGR valve, the working condition of an engine, the external environment and the state of a related actuator are judged, the condition that other interference exists in a closed loop space of a diagnosis function is eliminated, the judgment of the diagnosis function is influenced, an excitation signal is transmitted to the VGT actuator through the ECU, the VGT actuator can normally feed back a related control value after receiving the signal, and the ECU calculates the amplitude of the received signal according to Fourier transform after receiving the related feedback signal. And comparing the calculated value with the inherent threshold value to confirm and output the fault.

Drawings

FIG. 1 is a schematic diagram of the architecture of the intelligent VGT responsive fault diagnostic system of the present invention;

FIG. 2 is a flow chart of a method for diagnosing active responsiveness of an intelligent VGT actuator;

the notation in the figures means: 1-an engine; 2-VGT actuator; 3-a throttle valve; 4-EGR valve.

Detailed Description

The technical solution of the present invention is further described below with reference to the following embodiments and the accompanying drawings.

Example 1

The embodiment provides an active responsiveness diagnosis method for an intelligent VGT actuator, which comprises the following steps:

and S10, judging whether the EGR valve reaches the admission working condition or not according to the comparison result of the change of the set system flow and the set threshold value.

When the intelligent VGT actuator active responsiveness diagnosis method of the embodiment works, firstly, the admission condition of the diagnosis function needs to be judged. Eliminating the interference on the frequency of the system caused by the possible special working conditions or the action of the actuator. The diagnostic system is put in a relatively stable working state. The main sources of interference in the system are the EGR valve and the engine.

In this embodiment, in the control mode of the engine processing low idle speed, the boost pressure, the engine speed, the vehicle speed, the accelerator and the clutch need to meet the threshold requirement, and the torque is stable and meets the vibration requirement.

S20, engine temperature, ambient temperature, EGR valve position, throttle position, and boost control mode all meet the operating conditions.

And S30, calculating the diagnosis time t and the diagnosis success cycle number.

And S40, transmitting a sine signal of sin (2 pi tf) to the VGT actuator through the ECU, wherein f is a transmitting frequency and is approximately equal to a system natural frequency.

And S50, receiving a feedback signal r of the VGT actuator through the ECU.

by the formula

The corresponding system amplitude ω is calculated.

And comparing the amplitude threshold value after necessary correction through atmospheric pressure and ambient temperature with the calculated amplitude omega, and if the calculated amplitude is smaller than the threshold value, judging that the VGT has a response fault and the diagnosis is successful once.

According to the method for diagnosing the active responsiveness of the intelligent VGT actuator, firstly, the condition of an EGR valve, the working condition of an engine, the external environment and the state of a related actuator are judged, the condition that other interference exists in a closed loop space of a diagnosis function is eliminated, the judgment of the diagnosis function is influenced, an excitation signal is transmitted to the VGT actuator through the ECU, the VGT actuator can normally feed back a related control value after receiving the signal, and the ECU calculates the amplitude of the received signal according to Fourier transform after receiving the related feedback signal. Comparing the calculated value with an inherent threshold value to confirm and output the fault; therefore, the method does not need a large amount of data calibration work, and has high reliability and accuracy.

The sequence of the above embodiments is only for convenience of description and does not represent the advantages and disadvantages of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. An intelligent VGT actuator active responsiveness diagnostic method, comprising:

s30, calculating the diagnosis time t and the diagnosis success cycle number;

s50, receiving a feedback signal r of the VGT actuator through the ECU;

s60, obtained by changing the first-order fourier transform function S (t) a cos (2 pi tf) + b sin (2 pi tf):

by the formula

Calculating a corresponding system amplitude omega;

s70, the amplitude threshold value is corrected according to the atmospheric pressure and the ambient temperature and then compared with the calculated amplitude omega, if the calculated amplitude is smaller than the threshold value, the VGT has a response fault, and the diagnosis is successful;

in step S10, when the engine is in the low idle speed control mode, the boost pressure, the engine speed, the vehicle speed, the accelerator, and the clutch meet the threshold requirement, the torque is stable and the vibration requirement is met, and it is determined that the access operating condition is met.