CN107678419A - Intelligent VGT actuator active response diagnostic method - Google Patents

Abstract

The invention discloses an active responsive diagnosis method of an intelligent VGT actuator. The intelligent VGT actuator active responsiveness diagnosis method of the present embodiment, firstly, by the judgment of EGR valve, engine operating condition, external environment and the state of relevant actuator, get rid of other disturbances in the closed-loop space of the diagnosis function, which affect the diagnosis function Judgment, the ECU transmits the excitation signal to the VGT actuator, and the VGT actuator will normally feedback the relevant control value after receiving the signal. After receiving the relevant feedback signal, the ECU calculates the amplitude of the received signal according to the Fourier transform. The calculated value is compared with the inherent threshold value for fault confirmation and output.

Description

Active Response Diagnosis Method of Intelligent VGT Actuator

technical field

The invention belongs to the field of electronic control of automobile engines, and is a diagnosis method based on Fourier transform, which diagnoses the responsiveness of the actuator by actively exciting the actuator and judging the resonance effect.

Background technique

As environmental awareness continues to increase worldwide, vehicle emissions regulations are becoming increasingly stringent. At present, China has begun to implement the National IV emission regulations on a large scale, and the National V emission regulations have been implemented in developed regions such as Beijing and Shanghai. The National VI emission regulations will be implemented around 2020 in the future. The regulations will put forward clear requirements on the response performance of actuators that affect emissions, and it is necessary to make judgments on faults such as actuator sticking and carbon deposition.

In the structure of a new generation of diesel engines that meet the National VI emission regulations, VGT (variable cross-section turbocharger) will become the standard configuration of the engine. Cooperate with actuators such as EGR (exhaust gas recirculation) and throttle valve in the gas circuit system for coupling control to improve the combustion of diesel engines, control exhaust temperature, and optimize emissions. When the response performance of the VGT actuator decreases, the management strategy of the gas path will be significantly negatively affected, which will eventually lead to combustion deterioration and excessive emissions.

In traditional actuator responsiveness diagnosis, after the diagnosis condition is met, the current gas flow is compared with the calibrated threshold flow value under this working condition to make a judgment. This method requires calibration of a large amount of data, and the reliability and accuracy cannot be guaranteed. It is easy to misjudgment.

Contents of the invention

The purpose of the present invention is to address the difficulty of responsive diagnosis of traditional actuators, and propose an active responsive diagnostic method for intelligent VGT actuators, which is based on Fourier transform, generates resonance waveforms by actively exciting the actuators, and judges the execution by comparing the attenuation degree of the waveforms. Responsive state of the device.

The present invention solves the technical problem by adopting the following technical scheme: an active responsive diagnosis method for an intelligent VGT actuator, which includes:

S10, judging whether the EGR valve has reached the admission working condition according to the comparison result of the change of the set system flow rate and the set threshold value;

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

S30. Calculate the diagnosis time t and the number of successful diagnosis cycles;

S40, transmit a sinusoidal signal of sin(2πtf) to the VGT actuator through the ECU, where f is the transmission frequency;

S50. Receive the feedback signal r of the VGT actuator through the ECU.

S60, change according to the first-order Fourier transform function s(t)=acos(2πtf)+bsin(2πtf):

by formula Calculate the corresponding system amplitude ω;

S70. After making necessary corrections to the amplitude threshold value through the atmospheric pressure and ambient temperature, compare it with the calculated amplitude ω. If the calculated amplitude value is smaller than the threshold value, there is a responsive fault in the VGT, and the diagnosis is successful once.

The present invention has the following beneficial effects: the intelligent VGT actuator active response diagnostic method of the present invention firstly eliminates the presence of other faults in the closed-loop space of the diagnostic function by judging the EGR valve, the engine operating condition, the external environment and the state of the relevant actuators. Interference affects the judgment of the diagnostic function. The ECU sends an excitation signal to the VGT actuator. After receiving the signal, the VGT actuator will normally feedback the relevant control value. calculate. The calculated value is compared with the inherent threshold value for fault confirmation and output.

Description of drawings

Fig. 1 is the structural representation of intelligent VGT responsive fault diagnosis system of the present invention;

Fig. 2 is a flow chart of the active responsiveness diagnosis method of the intelligent VGT actuator;

The marks in the figure are: 1-engine; 2-VGT actuator; 3-throttle valve; 4-EGR valve.

detailed description

The technical solutions of the present invention will be further described below in conjunction with the embodiments and the accompanying drawings.

Example 1

This embodiment provides an active responsive diagnosis method for an intelligent VGT actuator, which includes:

S10 , judging whether the EGR valve meets the admittance working condition according to the comparison result of the change of the set system flow rate and the set threshold value.

When the active responsive diagnosis method of the intelligent VGT actuator in this embodiment works, it first needs to judge the access condition of the diagnosis function. Eliminate possible special working conditions or frequency interference caused by actuator actions to the system. Make the diagnostic system in a relatively stable working state. The main sources of disturbance in the system are the EGR valve and the engine.

In this embodiment, under the control mode where the engine handles low idle speed, the supercharging pressure, engine speed, vehicle speed, accelerator, and clutch need to meet the threshold value requirements, and the torque should be stable and meet the vibration requirements.

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

S30. Calculate the diagnosis time t and the number of successful diagnosis cycles.

S40. Transmit a sinusoidal signal of sin(2πtf) to the VGT actuator through the ECU, where f is the transmission frequency, which is approximately equal to the natural frequency of the system.

S50. Receive the feedback signal r of the VGT actuator through the ECU.

S60, change according to the first-order Fourier transform function s(t)=acos(2πtf)+bsin(2πtf):

by formula Calculate the corresponding system amplitude ω.

Make necessary corrections to the amplitude threshold value through atmospheric pressure and ambient temperature and compare it with the calculated amplitude ω above. If the calculated amplitude value is less than the threshold value, there is a responsive fault in the VGT, and the diagnosis is successful once.

The intelligent VGT actuator active responsiveness diagnostic method of the present embodiment, firstly, by the judgment of EGR valve, engine working condition, external environment and the state of related actuator, get rid of other disturbances in the closed-loop space of the diagnostic function, which affect the diagnostic function Judgment, the ECU transmits the excitation signal to the VGT actuator, and the VGT actuator will normally feedback the relevant control value after receiving the signal. After receiving the relevant feedback signal, the ECU calculates the amplitude of the received signal according to the Fourier transform. The calculated value is compared with the inherent threshold value to confirm and output the fault; it can be seen that this embodiment does not require a large amount of data calibration work, and the reliability and accuracy are high.

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

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (1)

1. An active responsive diagnostic method for an intelligent VGT actuator, characterized in that it comprises: S10, judging whether the EGR valve has reached the admission working condition according to the comparison result of the change of the set system flow rate and the set threshold value; S20, engine temperature, ambient temperature, EGR valve position, throttle valve position and boost control mode all meet the operating conditions; S30. Calculate the diagnosis time t and the number of successful diagnosis cycles; S40, transmit a sinusoidal signal of sin(2πtf) to the VGT actuator through the ECU, where f is the transmission frequency; S50. Receive the feedback signal r of the VGT actuator through the ECU. S60, change according to the first-order Fourier transform function s(t)=a cos(2πtf)+b sin(2πtf): <mrow><mi>a</mi><mo>=</mo><mfrac><mn>2</mn><mi>T</mi></mfrac><msubsup><mo>&amp;Integral;</mo><mn>0</mn><mi>T</mi></msubsup><mi>s</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><mo>&amp;CenterDot;</mo><mi>c</mi><mi>o</mi><mi>s</mi><mrow><mo>(</mo><mrow><mn>2</mn><mi>&amp;pi;</mi><mi>t</mi><mi>f</mi></mrow><mo>)</mo></mrow><mi>d</mi><mi>t</mi><mo>;</mo></mrow> <mrow><mi>b</mi><mo>=</mo><mfrac><mn>2</mn><mi>T</mi></mfrac><msubsup><mo>&amp;Integral;</mo><mn>0</mn><mi>T</mi></msubsup><mi>s</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><mo>&amp;CenterDot;</mo><mi>s</mi><mi>i</mi><mi>n</mi><mo>(</mo><mrow><mn>2</mn><mi>&amp;pi;</mi><mi>t</mi><mi>f</mi></mrow><mo>)</mo><mi>d</mi><mi>t</mi><mo>;</mo></mrow> by formula Calculate the corresponding system amplitude ω; S70. After making necessary corrections to the amplitude threshold value through the atmospheric pressure and ambient temperature, compare it with the calculated amplitude ω. If the calculated amplitude value is smaller than the threshold value, there is a responsive fault in the VGT, and the diagnosis is successful once.