Fault Characteristics and Maintenance Methods of Tractor Starting System

Abstract: The starting system is an important component of a tractor, which is directly related to the normal operation of the tractor. Therefore, it is necessary to pay attention to the operating status of the tractor starting system, understand its various fault characteristics, identify its fault causes, and take targeted maintenance methods to achieve the normal use of the starting system based on careful inspection to determine the cause of the fault. This article discusses and analyzes the fault characteristics and maintenance methods of the tractor starting system.

Key words: tractor starting system; Fault characteristics; Maintenance methods

To study the fault characteristics and maintenance methods of the tractor starting system, it is necessary to understand the basic structural characteristics and operating mechanism of the starting system, summarize the possible fault problems of the starting system at various stages and levels from multiple aspects, analyze the fault characteristics, formulate maintenance plans, select maintenance methods, improve the maintenance effect, and ensure that the starting system can play a role at critical moments.

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Overview of tractor starting system

1.1 Structural characteristics

The tractor starting system consists of a start switch, relay, starter, battery, etc. When starting the tractor, it is necessary to start the circuit system first, turn the key to the "ST" position, at this time, the relay is energized, and the subsequent battery maintains power to the starter, driving the engine to work; After the relay is turned off, the electromagnetic switch coil is turned on, and the diesel engine continues to be started. Turn the key to "ON", the starting circuit is directly disconnected, and the tractor stops working.

1.2 Operating mechanism

The operating mechanism is mainly aimed at the starter. Before starting the diesel engine, if it needs to rotate in advance in winter, it can complete the state transition of the diesel engine: stationary → running, and the diesel can run on its own after combustion. The traditional manual tractor has been difficult to meet the use requirements, and has been replaced by more advanced electric pneumatic technology. This technology uses a DC motor, and its starter structure consists of: housing, brush, clutch, armature, gear, and other auxiliary accessories; After inserting a key for ignition, it supplies power to the motor and completes the conversion of electrical energy to mechanical energy. After the current is generated, it will successively pass through equipment such as brushes, converters, excitation windings, and so on. Due to the role of electromagnetic fields in it, the armature coil will continue to maintain a uniform low speed operation in subsequent work, generating a starting torque, sucking in the moving iron core in the magnetic switch, allowing the pinion gear to dock with the flywheel gear ring, At this point, the armature coil will directly run at high speed after being powered, and the engine will officially start running. After the tractor operates, the key returns to the "ON" position and the moving iron core is pulled back [1].

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Analysis of Normal Operating Conditions of Tractor Starting System

The prerequisites for maintaining normal operation of the tractor starting system are focused on the following points:

2.1 Normal circuit system

Most tractors on the market use the electric starting method. Only when the entire circuit system is in normal condition can the electric starter, motor, etc. work normally, maintaining the stability and safety of the entire tractor system.

2.2 Normal air supply

Diesel engines can only be ignited when air is available, so it is necessary to check the air supply system for faults, defects, and other issues before starting to avoid negative impacts.

2.3 Normal fuel supply

The effect of fuel supply is mainly reflected in two aspects: one is that the fuel supply quantity is reasonable, which is the foundation and prerequisite for ensuring the normal operation of the diesel engine. The other is that the fuel supply timing is accurate, allowing the fuel to be injected accurately at the set time.

2.4 Normal startup speed

Starting operation is a necessary condition for achieving stable operation of a diesel engine. Only when the rotational speed is reasonable can it ensure that the diesel engine can always maintain a good operating state, and drive the fuel injection system to complete the oil mist supply, form a mixture in the cylinder, and complete the engine ignition and combustion [2].

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Fault Characteristics and Maintenance Methods of Tractor Starting System

Tractor starting systems have many components, and their fault characteristics are diverse, involving multiple aspects. Examples can be analyzed from the following points:

3.1 Starter fault problem

Starter is an important component of the starting system, and its fault problems are mainly manifested in:

1) The starter is difficult to operate normally. ① Fault characteristics. Manifestation: After turning on the start switch, it is found that the starter does not operate normally. The main reasons for this phenomenon are short circuit and poor foundation, depleted or insufficient battery power, and the inability of the electric system to work properly due to external force damage and electromagnetic switch damage Maintenance methods: First, check the entire starting circuit, observe for loose connections, check the firmness of key nodes such as battery terminals, and check the entire state of battery power through special tools or small electrical equipment. Then, use the replacement method to check whether the starter and electromagnetic switch are damaged. If they are damaged, they need to be repaired. If maintenance is difficult to reach their peak use status, they need to be replaced in a timely manner [3].

2) The starter transmission function fails to function. ① Fault characteristics. The main manifestations are: After the engine is started, although the starter can maintain normal operation, the diesel engine is difficult to operate, possibly due to significant wear on the flying gear ring teeth; It may also be due to slipping of the one-way clutch; If the fork is not installed in place, it may also cause problems; The armature stroke of the electromagnetic switch is too short, etc. ② Maintenance method: For this situation, it is necessary to promptly inspect the above accessories or equipment that may fail. If circumstances permit, for some equipment that is severely worn, it should be promptly replaced, and special personnel should be arranged to regularly inspect it, in order to avoid the recurrence of the same type of problems and achieve better results.

3.2 Difficulty in starting the tractor

In addition to the above starter problems, it may also be difficult to start the tractor due to the following fault problems:

1) The cylinder head nut is not tightened or damaged. ① Fault analysis. Check the crankshaft position for obvious air leakage. If yes, it indicates that it has not been tightened or has been damaged. ② Maintenance methods. If there is a problem due to not tightening, just tighten it directly; If it is damaged, it is necessary to observe the severity of the damage to the cylinder gasket. If there is no possibility of repair, it should be replaced directly. If the damage is minor, it can be repaired with asbestos wire, etc.

2) The piston is excessively worn. ① Fault characteristics. When the crankshaft is rotating, a sound of air leakage can be heard inside the engine body or at the position of the oil pan, which is basically a problem with the piston ring position Maintenance methods. Deliver an appropriate amount of clean engine oil to the inside of the cylinder. If it is found that the compression force has increased to a certain extent after adding it, you can directly replace the piston ring with a new one. After replacement, check its performance [4].

3) "The piston ring openings are moved to a straight line (commonly referred to as alignment), or the piston ring is stuck in the ring groove due to carbon deposition, and the compression cylinder cannot be ejected." Fault characteristics. When the crankshaft rotates, the sound of air leakage in the crankcase can be clearly heard Maintenance methods. Disassemble the piston ring and remove carbon from its internal and external surfaces; If the ring buckle moves to a straight line, it is necessary to maintain a uniform distribution of each opening position. This process avoids the direction of the piston pin, which can achieve better results.

4) The fixing bolts of the fuel injector are loose. ① Fault characteristics. Air leakage at the fuel injector on the cylinder head; The copper sleeve and bearing bush are stuck, but the crankshaft is difficult to rotate; Severe clogging of the air filter and reverse piston installation can also cause difficulties in starting Maintenance methods. Check the above possible fault problems one by one, conduct maintenance for the fault problems, and determine the source of the fault. If there is air leakage, it is necessary to retighten it. If there is a seizure, it is necessary to reorganize its routing and re regulate it. If the piston is installed reversely, it is necessary to reinstall it after stopping work. If there is a blockage problem, it is necessary to remove it and clean it up.

3.3 Compression system

If there are no problems with the above two items, abnormal starter startup still occurs, which may be caused by abnormal compression function:

1) The intake and exhaust valves leak. ① Fault characteristics. The reasons for this failure are concentrated in the following two points: First, the valve clearance is too small, causing the valve to fail to close; The other is that various spots appear on the valve sealing cone, such as carbon deposition, rust, etc., which can also affect the use effect of the valve Maintenance methods. If the former requires valve clearance adjustment in combination with its actual application, and if it requires a comprehensive inspection of the crankshaft, it is possible to continuously rotate the crankshaft. If a "squeak, squeak" sound is heard in the exhaust pipe and filter, it indicates that the exhaust and intake valves may have leaked air. In this case, the valve should be ground and its performance checked again after completing the repair to ensure that it meets the use requirements; In addition, it is necessary to check the spacing between the rocker arm head and the pressure reducing shaft to maintain its rationality; Check whether the cylinder head is loose, replace or adjust the cylinder head; It is also necessary to regularly clean the carbon deposits on the valve to avoid causing the tractor to overload and causing serious carbon deposits [5].

2) The valve clearance lacks rationality. ① Fault characteristics. During long-term operation of the tractor, the rocker arm bushing may be worn or burnt; Valve clearance changes due to external forces; The wear of the valve cam or tappet causes abnormal changes in valve clearance, resulting in abnormalities in the compression system Maintenance methods. If a change in valve clearance is found during inspection, it is necessary to clarify the specific reason for the change. First, it is possible to eliminate the wear of the rocker arm bushing caused by poor oil passages, or directly replace the rocker arm bushing with a more obvious performance advantage, and then match it with corresponding auxiliary equipment until it meets the requirements.

3) The cylinder compression function fails to work. ① Fault characteristics. The causes of cylinder compression performance failure are mainly concentrated in the following aspects: the piston and cylinder liner are roughened and worn; Cylinder gasket ablation; Deformation of connecting rod; The piston ring is broken or stuck. ② Maintenance methods. It is necessary to comprehensively inspect the application status of connecting rods, pistons, and cylinder gaskets, replace damaged and deformed parts, and clean up impurities such as carbon, dust, and water in the cylinder; The system checks the status of various positions such as the crankshaft and flywheel, and timely intervention is required in case of unexpected situations.

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epilogue

To sum up, this article discusses and analyzes the fault characteristics and maintenance methods of the tractor starting system, and recommends that sufficient attention be paid to them. Based on the actual operation of the tractor starting system, understanding its fault characteristics and taking this as a guide, selecting appropriate maintenance methods can achieve better maintenance results, ensure that the starting system returns to its normal use status in the shortest possible time, and maintain the long-term use of the tractor.