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Analysis of 5 Common Fault Causes of Sany Skid Steer Loader

Author: Site Editor     Publish Time: 2023-09-20      Origin: Site

When it comes to the operation and maintenance of Sany Skid Steer Loaders, understanding the most frequent fault causes is crucial. By recognizing these common issues, you can take proactive measures to prevent downtime and ensure optimal performance. Here, we delve into five classic fault causes that Sany Skid Steer Loader owners and operators should be aware of:

1. Why is it challenging to start a Sany skid steer loader during the winter?

Starting difficulties are not solely determined by the loader's technical condition but are also influenced by the external temperature. Initiating the engine in winter's cold climate poses several challenges due to the following factors:

  • Low Ambient Temperature: Winter brings frigid weather, causing the ambient temperature to plummet. This leads to an increase in the viscosity of the engine oil, resulting in higher friction among the engine's moving components. Consequently, this reduces the starting speed and makes ignition more challenging.

  • Decreased Battery Capacity: The cold weather causes a decline in the battery's capacity. This further hampers the starting speed.

  • Increased Air Leakage: A decrease in starting speed leads to higher air leakage and increased heat dissipation from the cylinder wall. This, in turn, reduces the temperature and pressure of the air at the end of compression. As a result, the delay period for diesel ignition is prolonged, and in severe cases, ignition may fail altogether.

  • Diesel Fuel Viscosity: Low temperatures cause the viscosity of diesel fuel to rise, slowing down the injection speed. Additionally, the air's swirl speed, temperature, and pressure at the end of compression are relatively low, leading to poor atomization quality of the injected diesel fuel. This poor atomization makes it difficult for the fuel to mix effectively with the air, potentially resulting in delayed ignition or even failure to ignite, thus complicating the starting process.

2. Why is the supercharger the most prone to failure on the engine?

This vulnerability stems from the fact that superchargers operate at rated speeds exceeding 130,000 revolutions per minute (rpm) and are situated at the exhaust manifold's outlet, subjecting them to extremely high temperatures (exceeding 800°C) and significant inlet and exhaust pressures. In essence, they endure conditions characterized by high temperature, high pressure, and high speed, demanding precise attention to lubrication, cooling, and sealing.

To ensure the longevity of the supercharger, specific design considerations are essential to maintain proper lubrication and cooling of the floating bearing within the supercharger. During usage, the following practices are recommended:

  • Gradual Startup: After ignition, allow the engine to idle for 3-5 minutes before applying any load to ensure adequate lubrication for the supercharger. This precaution is necessary because the supercharger is positioned atop the engine. A swift, high-speed start may fail to establish oil pressure promptly, potentially damaging or even causing the supercharger to burn out due to inadequate lubrication.

  • Limited Idling Time: Avoid excessively long idling periods, generally not exceeding 10 minutes, as prolonged idling can lead to oil leakage at the compressor end.

  • Proper Shutdown: Do not shut down the engine abruptly before parking. Instead, let it idle for 3-5 minutes to allow the supercharger's speed and the exhaust system's temperature to decrease, preventing issues such as heat regeneration, oil coking, bearing damage, and other potential failures. Frequent improper usage can harm the supercharger.

  • Preventative Measures for Inactivity: For engines that have been inactive for an extended period (typically more than 7 days) or those with newly installed superchargers, add engine oil to the supercharger's oil inlet before use to prevent reduced service life or supercharger damage due to insufficient lubrication.

  • Regular Inspection: Routinely inspect all connection points for looseness, air leaks, or oil leaks. Additionally, ensure the oil return pipe remains unobstructed, addressing any issues promptly.

  • Air Filter Maintenance: Maintain a clean air filter and replace it as recommended. Regularly replace the engine oil and oil filter as part of routine maintenance.

  • Shaft Clearance Inspection: Regularly check the radial and axial clearance of the supercharger shaft. Axial clearance should not exceed 0.15 mm, and radial clearance between the impeller and the pressure housing should be no less than 0.10 mm. If discrepancies arise, consult professionals for repairs to prevent further losses.

3. What causes the Sany skid steer loader to suddenly shut down during operation?

Sudden stalling of the engine during operation refers to the phenomenon that the engine stalls rapidly without releasing the accelerator due to factors other than the driver's operation while the engine is running, and cannot be restarted after stalling.

This phenomenon is generally caused by mechanical failure. The reasons are as follows:

  • Broken Fuel Injection Pump Drive Tooth and Faulty Transmission Gear: The engine may stall due to a broken fuel injection pump drive tooth or issues with the transmission gear.

  • Broken Fuel Injection Pump Shaft: If the fuel injection pump shaft breaks, it can lead to sudden engine stalling.

  • Internal Engine Parts Sticking: Stalling can occur if certain internal moving parts within the engine become stuck.

  • Fuel Injection Pump Control Rod and Connecting Pin Disconnection: The disconnection of the fuel injection pump control rod and connecting pin can also result in engine stalling during operation.

4. What causes the unstable idling of Sany skid steer loader?

Unstable engine idling is characterized by sudden fluctuations in idle speed, including sudden accelerations and decelerations, as well as vibrations that may lead to stalling when decelerating suddenly or shifting gears.

The detailed reasons behind this issue are as follows:

  • Air in the Fuel Line: The presence of air in the fuel line can disrupt smooth idling.

  • Poor Oil Supply in Low-Pressure Oil Line: If the low-pressure oil line does not provide an adequate oil supply, it can contribute to idling instability.

  • Improper Adjustment of Idle Speed Stabilizing Device: An incorrectly adjusted idle speed stabilizing device can lead to fluctuations in engine idling.

  • Poor Fuel Injector Atomization: When the fuel injector fails to atomize fuel effectively, it can result in unstable idling.

  • Uneven Fuel Supply from Fuel Injection Pump: Irregular fuel supply from the fuel injection pump can contribute to idling instability.

  • Excessive Wear on Pins and Forks of Speed Regulator Connecting Rods: If the pins and forks of the connecting rods in the speed regulator experience excessive wear, it can affect the engine's ability to maintain a stable idle.

5. While the engine runs smoothly at low speeds, it struggles to accelerate and displays weak driving capabilities due to insufficient circulating oil supply

The underlying reasons are as follows:

  • Improper Fuel Injection Pump Adjustment: Incorrect adjustment of the fuel injection pump leads to reduced fuel supply, hindering acceleration.

  • Fatigue in Speed Regulator Spring: The speed regulator spring may lose its elasticity due to fatigue. When the accelerator is fully depressed, the fuel volume adjustment lever fails to move forward, resulting in reduced fuel supply from the injection pump, preventing the engine from reaching its rated speed.

  • Wear of Fuel Injection Pump Components: Severe wear in components such as the plunger, sleeve of the fuel injection pump, needle valve of the fuel injector, and needle valve body can lead to increased diesel leakage during pumping, subsequently reducing fuel supply.

  • Improper Throttle Control Lever Adjustment: An improperly adjusted throttle control lever or a widened accelerator pedal pin prevents the accelerator pedal from reaching its intended position, resulting in inadequate fuel supply at full load.

  • Presence of Air in the Fuel Line: Air trapped in the fuel line can also contribute to reduced fuel supply.

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