Industrial diesel engines are engineered for durability, power, and efficiency, but how they are operated every day can significantly impact their performance and long term health. One of the most common, and often overlooked, habits that can hurt your engine and increase maintenance costs is prolonged light load operation.
What is light load operation?
When it comes to diesel equipment, light load operation means that the engine is working below 30% of its rated capacity. Prolonged light loading is when the engine operates below this 30% threshold for 75% or more of its total accumulated engine hours. Over time, this activity can lead to deteriorating performance, increased fuel consumption, and expensive repairs. Below are some of the negative effects that can result from extended periods of light load operation.
- Wet stacking and carbon buildup: A light engine load leads to lower combustion temperatures and incomplete fuel burn, which can result in unburnt fuel and carbon deposits building up in the exhaust system, exhaust gas recirculation (EGR) system, and diesel particulate filter (DPF). This material can eventually restrict air flow, causing overheating and potential engine damage.
- Poor fuel economy: Diesel engines are most efficient when operating near their peak torque range. Working well below this range wastes fuel.
- Oil contamination and degradation: Lower operating temperatures can lead to fuel dilution in the engine oil and increased condensation, which contaminates the oil and reduces its lubricating properties, accelerating wear and tear on internal components.
- Glazed cylinder liners: Prolonged periods of light loading can cause the cylinder liner walls to become glazed (polished), due to unburnt fuel and oil deterioration. Glazing can result in reduced oil retention, increased oil consumption, and potential loss of compression.
- Shortened engine life: The combined effect of carbon buildup, oil degradation, and glazing can lead to premature wear on critical components, significantly shortening the overall lifespan of the engine and increasing maintenance costs.
- Emission system issues: Modern diesel machines are equipped with sophisticated emission control technology. Low exhaust temperatures from light loading can keep these systems from reaching their necessary regeneration temperatures, resulting in frequent clogging, an increased number of active regenerations, and potential system damage.
Best practices to prevent diesel engine maintenance issues
To avoid the adverse effects related to light loading and ensure long term reliability and performance of your equipment, we have several recommendations to follow while operating your equipment:
- Effective load management: Whenever possible, run your diesel engines at or above the recommended 30% minimum load.
- Periodic load cycling: If you can’t avoid continuous light loading, implement regular intervals of higher load operation (e.g., 75%-100% load for a two hour period) to help burn off carbon deposits and bring engine components up to optimal operating temperatures.
- Proper sizing: Ensure engines are appropriately sized for their typical operational demands to prevent consistent light loading.
- Regular maintenance: Adhere strictly to the maintenance schedule recommended by the manufacturer, including oil changes and filter replacements, to remove potential contaminants.
If you have any questions about light loading or diesel engine maintenance, contact the Kelbe team today!