Diesel engines provide the power behind a significant percentage of over the road freight transport. These powerful internal combustion machines convert the chemical energy contained in diesel fuel to heat first and then to torque to drive big rigs for thousands of miles each day. Over time, in pursuit of increased efficiency, manufacturers have cleverly designed and built fuel and air handling systems to control the combustion process more precisely. Additionally, fuel conditioning systems such as the FASS fuel air separation system may be employed to improve efficiency ahead of the cylinders. The purity of both fuel and air components must be carefully monitored and controlled to realize maximum performance.

Combustion engines used for freight transport must operate over a wide range of conditions. Delivery destinations include low elevation, humid, coastal areas to desert climates to freezing temperatures and high elevation mountain passes. Consistently efficient performance throughout this variety of environmental conditions is a challenging task. When high operating temperature is added to the equation physical and chemical processes are often accelerated causing corrosion or other deterioration.

A relatively common maintenance issue that arises in diesel engines is the contamination of the fuel system. Several different types and sources of contamination are possible. The most effective approach to preventing engine damage due to this problem is careful monitoring and proper routine maintenance. Some of the different types of contaminants include air, water and particulates.

Air Contamination

It might seem counterintuitive that air could be a contaminant in fuel because ultimately oxygen is required for the combustion process. However, when gases become entrained in the fuel it negatively impacts the precision delivery and atomization of fuel in the injector system. The result can be interference with ignition and incomplete combustion which, in turn, causes increases in exhaust containing higher levels of pollutants.

Water Contamination

Diesel fuel is hygroscopic meaning it is chemically predisposed to absorb water vapor from the atmosphere. If fuel is stored in tanks that are not maintained at full capacity, water is literally drawn out of the humidity in the air above the fuel. Water in the fuel reduces engine efficiency and, in some cases, if it is not removed by fuel filters may cause injectors to explode resulting in catastrophic engine damage.

Particulate Contamination

Pieces of solid matter such as rust or sand in the fuel supply result from deteriorating storage tanks or poor fuel handling practices. These solid particles can clog up fuel filters rapidly which restricts fuel flow to the injectors and can dramatically reduce engine performance.

Maintaining diesel engines in top operating condition requires regular maintenance procedures and careful monitoring. Standards for fuel handling and storage help to reduce the incidences of contamination so big rigs keep rolling and freight gets delivered.