CN109782742B

CN109782742B - Slow response diagnosis method for actuator

Info

Publication number: CN109782742B
Application number: CN201910095049.2A
Authority: CN
Inventors: 陈铁; 张鹏; 王明卿; 李凡杰; 杨茜
Original assignee: FAW Jiefang Automotive Co Ltd
Current assignee: FAW Jiefang Automotive Co Ltd
Priority date: 2019-01-31
Filing date: 2019-01-31
Publication date: 2021-06-22
Anticipated expiration: 2039-01-31
Also published as: CN109782742A

Abstract

The invention discloses a slow response diagnosis method for an actuator, which belongs to the field of electronic control of automobile engines and aims at the difficulty of response diagnosis of the traditional actuator. The rate of slow response fault occurrence can be accurately represented through the time accumulation of slow response occurrence, so that the slow response fault diagnosis is more accurate, and the fault occurrence can be accurately identified.

Description

Slow response diagnosis method for actuator

Technical Field

The invention belongs to the field of electronic control of automobile engines.

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 diesel engine structure meeting the national VI emission regulations, an electric control adjustable supercharging system is matched with actuators such as an EGR (exhaust gas recirculation) valve and a throttle valve in a gas circuit system for coupling control, so that the combustion of the diesel engine is improved, the exhaust temperature is controlled, and the emission is optimized. When the response performance of each actuator is reduced, the management strategy of the gas circuit is obviously and negatively influenced, and finally, the combustion is deteriorated, and the emission exceeds the standard.

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, reliability and accuracy cannot be guaranteed, and misjudgment is easy to generate.

Disclosure of Invention

Aiming at the difficulty of the responsiveness diagnosis of the traditional actuator, the responsiveness state of the actuator is judged by comparing the change rate of the slow responsiveness state in the dynamic working condition through the time integral change rate.

The adopted technical scheme is as follows:

an actuator slow response diagnosis method comprises the following specific steps:

1) firstly, the admission condition of the diagnostic function needs to be judged, which is as follows:

A. whether the cooling liquid meets the requirement of a threshold value of 60 ℃;

B. the atmospheric temperature meets the requirement of an interval of-7 ℃ to 35 ℃;

C. the atmospheric pressure meets the requirement of 75 kPa-110 kPa threshold value;

D. the oil quantity needs to meet the upper and lower limit values Q_min～Q_maxInterval, lower limit value Q_minAnd an upper limit value Q_max(mg/st) inquiring an oil quantity chart of the rotating speed actuator according to the current rotating speed value to determine.

2) And when the admission condition is met, calculating dynamic response.

When judging formula

|V_pos-V_poslowpass|＞V_posthd (1)

When the condition is met, the dynamic calculation working condition A is confirmed to enter through 0.5s of time delay, and if the flag _ a is 1, otherwise, the flag _ a is 0; wherein, V_posFor controlling the output value of the actuator, V_poslowpassFor controlling the output value, V, of the filtered actuator_posthdFor the determination of the threshold value, pass V_poslowpassThe two-dimensional threshold value chart is obtained by looking up a table, and the range is 5% -10%.

Setting:

wherein, V_posfbFeedback value of actuator sensor, if B > A, the current cycle actuator is considered to be ringingStress slow event occurrence flag _ b is 1 or else flag _ b is 0.

The dynamic working condition flag _ a and the slow response flag _ b are respectively subjected to the accumulation processing of the discretization system,

according to the function y ═ u × Td + Ti_LastThe calculation is carried out in such a way that,

wherein y is the accumulated time output value, u is the flag input, including flag _ a and flag _ b, Td is the time step length, the time step length is equal to the calling period of the corresponding judgment system of the actuator, and Ti_LastEqual to the time output value y of the previous calculation cycle, and the initial value is 0.

And the dynamic working condition flag _ a and the slow response flag _ b are calculated by the function to respectively obtain the dynamic working condition duration TIA and the slow response working condition duration TIB.

And if the TIA does not meet the threshold requirement, the actuator is considered to be in the dynamic working condition for insufficient time, and the diagnosis is continued. If the time exceeds a threshold value, the rate of change α of the TIA/TIB is calculated, and if the rate of change α is greater than the rate of change threshold value, the diagnosis is considered to be successful. Outputting a fault mark theta equal to 1; the threshold values for the rate of change α and the duration of the dynamic condition may be obtained by calibration.

The invention has the beneficial effects that:

the invention can accurately show the rate of slow response fault occurrence through the time accumulation of slow response occurrence, so that the slow response fault diagnosis is more accurate, and the fault occurrence can be conveniently and accurately identified.

Drawings

FIG. 1 is a schematic diagram of an actuator responsive fault diagnostic system.

FIG. 2 is a diagnostic control method.

Detailed Description

The actuator active responsiveness diagnosis system is a closed loop system consisting of an engine, a VGT actuator, a throttle valve, an EGR valve and the like. And the ECU is used for monitoring and calculating the control and feedback quantity.

2) And when the admission condition is met, calculating dynamic response.

When judging formula

|V_pos-V_poslowpass|＞V_posthd (3)

Setting:

wherein, V_posfbAnd (4) an actuator sensor feedback value, if B is larger than A, considering that the response slow event occurrence flag _ B of the current cycle actuator is 1, and otherwise, considering that the response slow event occurrence flag _ B is 0.

wherein y is the accumulated time output value, u is the flag input, including flag _ a and flag _ b, and Td is the time step equal to the calling period of the corresponding judgment system of the actuator, e.g. 10ms, Ti_LastEqual to the time output value y of the previous calculation cycle, and the initial value is 0.

If the time TIA does not meet the requirement of the threshold value 2s (the time length can also be calibrated according to the requirement), the time that the actuator is in the dynamic working condition is considered to be insufficient, and the diagnosis is continued. If the time exceeds a threshold value, the rate of change α of the TIA/TIB is calculated, and if the rate of change α is greater than a threshold value of 0.5 (which may also be calibrated as required), the diagnosis is considered successful. The output failure flag θ is 1.

The time delay is made for the entry and exit of the fault theta through the debounce calculation (the specific delay time can be adjusted as required).

Claims

1. An actuator slow response diagnostic method is characterized by comprising the following specific steps:

D. the oil quantity needs to meet the upper and lower limit values Q_min～Q_maxInterval, lower limit value Q_minAnd an upper limit value Q_max(mg/st) inquiring an oil mass chart of the rotating speed actuator according to the current rotating speed value to determine;

2) when the admission condition is met, entering the calculation of dynamic response;

when judging formula

|V_pos-V_poslowpass|>V_posthd (1)

When the condition is met, the dynamic calculation working condition A is confirmed to enter through 0.5s of time delay, and if the flag _ a is 1, otherwise, the flag _ a is 0; wherein, V_posFor controlling the output value of the actuator, V_poslowpassFor controlling the output value, V, of the filtered actuator_posthdFor the determination of the threshold value, pass V_poslowpassThe two-dimensional threshold value chart is obtained by looking up a table and has a range of 5% -10%;

setting:

wherein, V_posfbThe actuator sensor feedback value, if B is larger than A, considering that the response slow event of the current cycle actuator occurs flag _ B to 1, otherwise flag _ B to 0;

wherein y is the accumulated time output value, u is the flag input, including flag _ a and flag _ b, Td is the time step length, the time step length is equal to the calling period of the corresponding judgment system of the actuator, and Ti_LastEqual to the time output value y of the previous calculation cycle, with an initial value of 0;

after the dynamic working condition flag _ a and the slow response flag _ b are calculated by the function, the dynamic working condition duration TIA and the slow response working condition duration TIB are respectively obtained;

if the TIA does not meet the threshold requirement, the time that the actuator is in the dynamic working condition is considered to be insufficient, and diagnosis is continued; if the time exceeds a threshold value, calculating the change rate alpha of the TIA/TIB, and if the change rate alpha is larger than the change rate threshold value, judging that the diagnosis is successful; outputting a fault mark theta equal to 1; the threshold values for the rate of change α and the duration of the dynamic condition may be obtained by calibration.