On the relationship between diesel quality and the proper operation of engines

Cold flow point, flash point, and cetane number all have a significant impact

I found this information online: 1. Incomplete combustion leads to increased fuel consumption (diesel contains more dust and impurities). When a diesel engine is operating, the fuel is injected into the cylinder by an injection pump, and the high injection pressure generated by this pump is what drives the fuel injection. If low-quality diesel containing many impurities and dust is used, the nozzles are prone to clogging, which reduces the operating pressure of the injector and weakens the atomization effect, resulting in oil droplets. This leads to inadequate mixing of diesel with air, and consequently incomplete combustion. Some of the unburned diesel is discharged along with the exhaust gases, resulting in reduced power performance and increased consumption. At the same time, when the fuel injection pump and injectors are in operation, the corrosion caused by low-quality diesel on the valve components of the fuel injection pump and the plunger components of the injectors can lead to excessive wear, resulting in severe premature wear of these components. This in turn causes a decrease in power output, increased fuel consumption, and higher emissions. 2. Accelerated mechanical wear (diesel contains a high amount of dust and impurities). Since the clearance between the components of the fuel injection pump’s plunger, outlet valve, and injector is very small, and lubrication is provided by diesel during operation, the use of diesel with high levels of dust and impurities will accelerate the mechanical wear of these three precision components. Worn plunger assemblies will **reduce** the sealing performance, causing the oil pump’s oil supply volume to drop rapidly ； The lower the rotational speed, the weaker the throttling effect, the greater the leakage, and the more significant the reduction in fuel supply – all of which are detrimental to the starting and operation of the diesel engine. Impurities in diesel cause the worn piston rings and cylinder liners to have reduced sealing performance, resulting in insufficient compression force and a decrease in power output. If diesel contains, in addition to non-combustible mechanical impurities such as dust, salts of organic and inorganic acids that are soluble in diesel, it will increase the hardness and corrosiveness of the carbon deposits, causing the cylinder liners to be scratched or stuck to the cylinder walls, resulting in severe damage to the cylinder liners. 3. Reduced power and increased fuel consumption (due to excessive changes in diesel viscosity). Using diesel with too low viscosity can break the oil film around the plunger and nozzles, leading to poor lubrication, increased oil leakage, and a reduced penetration depth of the diesel in the combustion chamber; this in turn reduces the service life and output power of the diesel engine. On the other hand, diesel with too high viscosity causes the diesel particles ejected from the injector to become larger, making it difficult for them to be heated, vaporized, and oxidized quickly ； This will result in uneven air-fuel mixture, incomplete combustion, black smoke from the exhaust, increased fuel consumption, and reduced engine efficiency. The viscosity level also affects the fuel supply volume of the fuel injection pump; lower viscosity results in a reduced fuel supply volume ； High viscosity will increase the fuel supply volume; therefore, in practical operation, the fuel pump’s supply volume must be adjusted accordingly to the changes in the viscosity of the diesel used. 4. Chemical corrosion (high-sulfur diesel): When diesel with a high sulfur content is used, combustion produces excessive amounts of sulfur dioxide and sulfur trioxide gases. When these gases come into contact with condensed water in the cylinders and exhaust pipes, sulfurous acid or sulfuric acid is formed, leading to chemical damage to the injectors, cylinder liners, and pistons. Additionally, the combustion of high-sulfur diesel results in the formation of hard carbon deposits that scratch the cylinder walls, increasing mechanical wear. In addition, sulfur-containing exhaust gases can also enter the crankcase, **increasing lubricant deposits and accelerating the aging and deterioration of the lubricant, thereby worsening its lubricating properties. 5. Causing tile burning accidents (excessive moisture in diesel). If diesel with high moisture content is used, it can cause the injectors and pistons to sinter and rust. Some drivers, when topping up the fuel pump with oil on a regular basis, rarely drain the old oil from the pump before replacing it. As a result, if there are leaks in the fuel pump or pistons, water will flow into the pump along with the diesel. Since water is denser than oil, it settles at the bottom of the pump chamber, accumulating over time. Once enough water has accumulated, it will mix with the oil as the camshaft rotates rapidly, forming an emulsion. This not only disrupts normal lubrication, but over time the components inside the entire oil pump will rust to varying degrees, causing the plunger assembly and the oil volume control mechanism to become inflexible or even get stuck. In low-temperature environments, water in diesel is prone to freezing or forming small ice crystals, which causes the diesel to become cloudy and clogs the filters; in severe cases, this can lead to a disruption in fuel supply. 6. Excessive carbon buildup: If diesel with a high level of residue or excessive acidity is used, excessive carbon buildup will occur in the combustion chamber. Carbon buildup at the tip of the fuel injector reduces the spraying efficiency, resulting in black smoke in the exhaust gases. 7. Erosion formation: The use of diesel containing water-soluble acids or bases can cause severe erosion to the diesel engine ； If the content of organic acids is too high, it can cause corrosion of containers, fuel supply equipment, and other components, accelerate coking in the fuel injectors, and disrupt normal fuel supply.