Analysis and solutions to common faults of drilling rigs!

1. Why is it difficult to start a drilling rig in winter? It is not only determined by its own technical condition but also influenced by the ambient temperature. Starting at low temperatures during winter presents significant challenges due to several factors:

⑴ Cold winter conditions lead to decreased temperatures, which increase the viscosity of the engine oil and augment friction among moving parts, thus hindering the starting speed and making ignition difficult.

⑵ The capacity of the battery diminishes as temperatures drop, further impacting the ability to achieve adequate starting speed.

⑶ A reduced starting speed results in greater leakage of compressed air, along with increased heat dissipation from the cylinder walls; both factors contribute to a marked decrease in temperature and pressure of the injected air, subsequently extending the delay period of diesel ignition and potentially leading to failure to ignite.

⑷ The viscosity of diesel fuel also rises at low temperatures, which decreases its injection speed. Coupled with lower swirl speed and reduced temperature and pressure at the end of compression, this results in poor atomization of the injected diesel. Consequently, it becomes challenging to form a combustible mixture with the air efficiently, impeding timely ignition and, in severe cases, leading to a complete failure to ignite.

2. What conditions improve the starting performance of a Jinke drilling rig? Several key factors must be met to enhance starting characteristics:

⑴ Adequate starting speed is critical. Higher speeds reduce gas leakage within the cylinder, minimize the time for heated compressed air to transfer energy to the cylinder walls, and consequently reduce heat loss. Generally, an optimal speed of over 100 r/min is required.

⑵ The sealing integrity of the cylinder must be effective. This prevents excessive leakage and ensures enough combustion temperature and pressure at the end of compression, with compression pressure maintained at no less than 80% of the standard level.

⑶ Proper clearance and lubrication between the engine and its moving components are essential for smooth operation.

⑷ The battery must possess sufficient starting capacity, and the overall condition of the starting circuit should be normal.

⑸ The starting oil volume must align with required specifications, ensuring quality injection and correct advance angle settings.

⑹ Finally, utilizing fuel that meets defined requirements is crucial for optimal performance.

3. Diagnosis and repair of mechanical issues arise when the crankshaft fails to rotate during drilling rig startup. If the starting system appears functional but pressing the start switch only produces sound without any crankshaft movement, it indicates mechanical failure. The potential reasons for the crankshaft's inability to rotate are:

① Improper meshing between starter and flywheel. If teeth on the ring gear and starter gear do not engage correctly, it can result in damage or uneven wear of the teeth. More than three damaged teeth can impede proper meshing of the starter gear with the ring gear.

② Cylinder binding may occur. In instances of excessive engine temperature, an engine that is turned off may struggle to dissipate heat, leading to piston rings sticking to the cylinder upon cooling, thereby obstructing the start.

③ Crankshaft seizure due to lubrication system failure or a lack of engine oil can lead to dry friction in sliding bearings, locking the crankshaft and preventing startup.

④ The injection pump plunger may also be obstructed, adding to starting complications.

4. For a drilling rig that can rotate upon starting but does not ignite (evident by no smoke from the exhaust pipe), this generally points to oil circuit issues. The detailed analysis includes:

① Fuel tank devoid of oil.

⑵ Blockages in the fuel filter or oil-water separator.

③ Absence of oil supply within the low-pressure oil circuit.

④ Malfunctioning fuel injection pump failing to pump oil.

⑤ Presence of air in the oil circuit.

⑥ Inaccurate valve timing can disrupt coordination between valve openings and the piston’s stroke, leading to situations where fresh air is expelled instead of allowing combustion gases in, thus blocking ignition.

⑦ A malfunctioning solenoid valve in the fuel injection pump may prevent diesel from entering the high-pressure chamber.

5. When a drilling rig faces difficulties starting or fails to ignite, resulting in significant white smoke emission from the exhaust pipe, the potential causes are:

① Presence of water in diesel, which evaporates into vapor within the cylinder, escaping through the exhaust pipe.

② Loose cylinder head bolts or damaged cylinder gaskets that allow cooling water to seep into the cylinder.

③ Cracks or sand holes in the cylinder block or head that permit water infusion, leading to evaporation and discharge.

6. A rig struggling to start accompanied by gray-white smoke from the exhaust suggests diesel vapor is a contributing factor. The reasons include:

① Insufficient engine temperature leading to poor diesel evaporation and combustion.

② Ineffective atomization by the injector.

③ Delay in fuel supply timing.

④ Inadequate fuel supply resulting in overly lean mixtures.

⑤ Excessive cylinder leakage prevents the ignition temperature from being reached at the end of compression.

7. A rig facing challenges in starting with black smoke emanating from the exhaust signifies incomplete diesel combustion. Possible implications include:

① Poor quality of diesel fuel.

② Restricted air intake due to a blocked filter.

③ Incorrectly set injection timing that is too early.

④ Poor sealing of the injection needle valve, leading to fuel leakage.

⑤ Low injection pressure hampering effective combustion.

⑥ Excessive fuel supply from the injection pump resulting in deterioration of combustion.

⑦ Low cylinder pressure that impairs effective atomization.