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Method for fault diagnosis of agricultural tractor

2017/5/12

1. Separation method

It is a method of partially blocking or blocking the work of a certain system or a certain component, and determining the fault range by observing the change of the sign. After the part is removed or cut off, if the fault phenomenon is immediately eliminated, it means that the fault occurred in this place; if the fault phenomenon still exists, it indicates that the fault is in other places.

For example: use the broken cylinder method to determine the faulty cylinder position. When the engine emits black smoke, if a certain cylinder is cut off, the black smoke is immediately eliminated, indicating that the fault occurred in this cylinder, and then the cylinder is further inspected.

Also, the failure section is determined by intermittently cutting off a certain power transmission line. The shift lever can be placed in the neutral position to intermittently engage and disengage the clutch, audibly changing the sound to determine if the fault is in the clutch or in the transmission. When diagnosing an electrical system failure, it is also common to temporarily isolate a certain line to determine the fault range.

2, heuristics

For some parts of the fault range, the method of judging whether it is normal or not by tentative exclusion or adjustment measures.

When using the heuristic method, the disassembly should be minimized, and the parts should be prevented from being broken down into parts. When making tentative adjustments, it is necessary to take into account the possibility of restitution and to confirm that there are no adverse consequences. It is also necessary to avoid several tentative adjustments at several locations or at the same time to prevent mutual confusion.

3. Comparison method

Replace the suspected part with the same piece that is working properly, and judge whether it is faulty according to the change of the sign. For example, if the injector of a cylinder is suspected to be not working properly, the injector of this cylinder can be replaced with another injector that is working normally.

4. Experience method

Relying on the operator's ear, eyes, nose, hands and other organs to determine the technical state of each part of the good or bad.

According to the characteristics of the sound produced when the tractor is running, it is judged whether the technical state of the fitting is good or not. This is auscultation.

Observation is to observe all visible phenomena with the naked eye, such as exhaust smoke, oil color, crankcase venting, etc., in order to find problems in time.

Smell: Identify and identify faults in certain parts in time by sniffing the smell of exhaust smoke or burning odor.

Touch: Use the feeling of the hand to judge whether the working temperature or the gap is normal.

The empirical method has certain practical value. However, based on the state of the sensory organs, it is necessary to continuously experience, explore, and summarize their experiences in the long-term practice.

5, instrument method

Use light instruments and meters to accurately understand the internal state without disassembly or disassembly. The instrument method has the following advantages: First, it can accurately and qualitatively and quantitatively analyze the technical state of each part. And can help us quickly improve the ability to diagnose faults. Then there are advanced and reliable inspection methods and methods, which can shorten the fault diagnosis time.