Challenges of Diesel Generators Operating in Cold Conditions

 
Operating a diesel generator in low-temperature environments presents numerous challenges and potential issues. These conditions can significantly impact the generator's performance and longevity. Understanding the specific effects of low temperatures on diesel generators is crucial for maintaining efficient and reliable operation. This article provides a detailed analysis of the primary impacts of low temperatures on diesel generators, including issues related to lubricating oil, cylinder corrosion, fuel consumption, part expansion, starting difficulties, oil performance, thermostat removal.

Issues with Lubricating Oil

 
When the cooling water temperature is too low, the lubricating oil temperature decreases accordingly. At low temperatures, the viscosity of the lubricating oil increases, and its fluidity becomes worse. This not only increases the wear of the generator set parts, but also leads to increased mechanical power loss due to greater resistance in the movement of the parts, ultimately resulting in a reduction in the output power of the generator set.

Cylinder Corrosion

 
When the ambient temperature is too low, the cylinder temperature will also be very low, making it easy for water vapor inside the cylinder to condense on the cylinder wall. Sulfur dioxide produced during the combustion of diesel encounters this condensed water, forming a strong corrosive agent that adheres to the cylinder wall. This can lead to a loose metal structure on the surface of the cylinder wall, accelerating wear. When the cylinder liner and piston rings rub against each other, the corroded layer with a loose metal surface will wear off quickly, or pits and depressions may appear on the working surface of the cylinder liner.

Increased Fuel Consumption

 
At low temperatures, the cooling water carries away a significant amount of thermal energy from the cylinder, increasing heat loss. The mixture of gases does not form and burn effectively, which can lead to an increase in fuel consumption by 8% to 10%. When fuel in droplet form enters the cylinder, it washes away the lubricating oil film on the cylinder wall and seeps into the crankcase. This results in increased wear on the parts, dilution of the lubricating oil in the oil pan, increased fuel consumption, and reduced power output.

Insufficient Part Expansion

 
Some parts that expand when heated may not expand to their proper dimensions due to low temperatures, thereby affecting the overall performance of the machine. For instance, if there is too much clearance between the piston and the cylinder, the sealing will be poor; if the valve clearance is too large, it can be impacted by the rocker arm, etc. All these factors can make it difficult to start the diesel generator.

Difficult Starting

 
When a diesel engine operates, the high temperature of compressed gas is essential to ensure fuel ignition. When the temperature of parts like the cylinder and piston drops, the final compression temperature decreases, causing delayed ignition and poor combustion conditions. This results in incomplete fuel combustion, rough engine operation, and exhaust smoke. In icy conditions, especially below -20°C, the most notable problem is that the diesel generator cannot start. The electrolyte in the battery and cooling water can freeze, damaging the engine, radiator, and battery, while exacerbating component wear.

Decline in Oil Performance

 
In low-temperature environments, increased engine oil viscosity, reduced penetrating ability, and enhanced internal resistance can cause a sudden drop in battery capacity and terminal voltage, weakening the battery's discharge capability. Excessively viscous oil increases the resistance of moving parts such as the crankshaft, pistons, and rotating gears. A weakened battery discharge reduces starting torque for the starter motor, slowing the crankshaft rotation and piston movement. This results in a slow compression stroke, gas leakage, increased heat loss through the cylinder walls, and a sudden decrease in the final compressed air temperature and pressure.

Impact of Removing the Thermostat

 
In low-temperature environments, some operators may remove the thermostat to keep the diesel generator in a continuous large circulation state. This practice can lead to a significant loss of heat carried away by the cooling water and cold air, increasing thermal losses, reducing the power output of the diesel generator, and increasing fuel consumption.

Battery Performance Decline

 
In low-temperature environments, the performance of batteries in diesel generators is also significantly affected. Low temperatures reduce the rate of chemical reactions in batteries, leading to a decrease in discharge capacity, making it more difficult to start the generator. In addition, low temperatures also lead to a decrease in the charging and discharging cycle efficiency of batteries, shortening their service life. The voltage fluctuates greatly during the battery discharge process, which may interfere with the electronic control system of the generator, affecting its normal operation.
 
In summary, the impact of low temperatures on diesel generators is multifaceted, ranging from issues with lubricating oil to increased wear on parts, higher fuel consumption, and difficulties in starting. These effects not only degrade the performance of diesel generators but also significantly reduce their service life. Therefore, when operating diesel generators in low-temperature environments, it is essential to take appropriate protective measures to ensure their normal operation and longevity.