Welcome to number one hundred big fat Carry a hoe, as Car enthusiasts today to tell you a little about the basics of Car maintenance electrician. According to yesterday to introduce the Automotive electrical system failure and repair methods, today to introduce an electronic control system maintenance base! The method
1, the data flow analysIs
The data flow analysIs Is the use of the Automobile vehicle fault diagnostic control system sensors, actuators and run computer analysIs parameters and parameter control process multiple simultaneous measurements, which data stream based diagnostic testing capabilities, data flow synchronous dynamic, multi-parameter characterIstics simultaneously dIsplayed, and therefore, can provide extremely rapid analysIs of Car trouble big convenience. DIsplay (1) data stream. DIsplay data flow are: numerical dIsplay, bar graph dIsplay and waveform dIsplay three kinds can be selected as necessary. 1) values are dIsplayed. Numerical data stream dIsplay mode Is the most common dIsplay, comprIsing a main data name and data values (including analog and digital), data value changes at a frequency of 2 ~ 3s refresh on the dIsplay screen with time. Data show that the whole group Is divided into the number of dIsplay, selection and dIsplay the group dIsplay.
2) bar dIsplayed. Bar graph dIsplay, also known as a bar graph dIsplay, such data Is an analog value dIsplayed pointer dIsplay instrument, having good characterIstics observed value change process, the bar graph value (or hIstogram) of large and medium data black stripe (or columnar) while the size of numerical pattern with left (or up and down) change, a small change trend may provide a better vIsual effect for the user, while also accurately dIsplayed along the meters. 3) the waveform dIsplay. Waveform dIsplay Is a graphical dIsplay of the data stream, in thIs way not only the dynamic change dIsplay of data, but also the process of completely changing trends reflect the value, the waveform dIsplay Is a two-dimensional coordinate value data and the time dIsplay mode, thIs dIsplay can easily express numerical data trends over time and dynamic, it Is a powerful tool for time-frequency analysIs.
For the same waveform multiplexed data screen dIsplayed in the dIsplay change process of ways of data while also having a time phase between the data and data analysIsFeatures. It clearly shows the interconnections between the ways of data signals, e.g. causality and relationships. AnalysIs Method (2) data stream. Measured by a series of data stream data Is analyzed, there Is a fault based on certain elements. Common data flow analysIs methods range analysIs, five, time domain analysIs, cause and effect analysIs, correlation analysIs and comparative analysIs method. 1) range analysIs. Numerical analysIs range Is the range of variation of a certain size and data, and to determine the fault by the size and range of values, Is one-dimensional analysIs of the data value axIs. First, the analysIs range Is determined whether the limit Is exceeded the numerical ranges according to the fault codes to determine a short or open circuit fault.
2) time domain analysIs. Time domain analysIs Is to examine the change in frequency and the variation period of the data, analyze patterns of a time-varying data, the method by rule of data values over time to determine the fault. When the city of analysIs Is two-dimensional analysIs of the data and time coordinates. For example, the oxygen sensor value change must be constantly varied during closed-loop control, the engine hot Car, the ammonia sensor output signal changes up and down in 0. 45V Cultivation partner must be greater than 4 times / 10, which Is a feedback fuel control system limit of normal work.
3) causal analysIs. AnalysIs causal analysIs law of causality between the plurality of data, and the passage of the clearance of the research data to support the clothes put eye Is now a result of a State, Country State dodine step 2 AnalysIs of a portion of several shadow two conditions or the size of a plurality of data values with the following interrelated sent for analysIs Is now present, among the plurality of interrelated States need to change data associated with the analysIs to determine fault. 5) comparative analysIs. Comparative analysIs Is a failure when the vehicle Is in fault-free conditions with the vehicle at a data set of the same conditions for comparative analysIs data set, or the data in the same conditions of similar models comparIson of methods to determine the fault point group thereto.
the next Issue we Will continue to analyze the basic knowledge about vehicle maintenance electrician!
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