Search Results

With the pending introduction of ultra low sulfur diesel fuel, lubricity is becoming a more pressing concern. It has long been recognized that certain additives can dramatically improve fuel lubricity. However when manual addition of liquid additives is used to treat fuels human error can be introduced resulting in incorrect additive concentration or use of an inappropriate additive. To overcome the issues with manual additive addition and provide additional protection for customers using poor lubricity fuels a slow release lubricity enhancing fuel filter was introduced in 2002. This filter was effective but had some limitations. To address these limitations and to further optimize this technology a novel release mechanism was developed and introduced in 2006. This paper will document the development and validation of this technology.

It has long been asserted that optimizing injector cleanliness (preventing the formation of deposits and removing them if they are present) can have a positive impact on fuel economy for heavy-duty diesel engines. However limited amounts of field data exist on more recent engines to support these claims. Also, factors such as small test sample size, varying BTU content of fuel and inconsistent duty cycles in test vehicles can often skew fuel economy study results in a field-test environment. This paper will detail an extensive field study (in which care was taken to minimize the effects of the above mentioned factors that can introduce error) to analyze the effect of consistent dispersant/detergent usage on fuel economy for a grocery delivery fleet.

Low lubricity diesel fuels have long been problematic when used in fuel systems due to increased wear tendencies of these types of fuels1. It has been demonstrated that a variety of additives can dramatically increase lubricity for diesel fuels, even at low treatment rates. However these additives must be added consistently for fuel systems to see the benefits associated with enhanced lubricity fuels. That is not always possible in field applications when drivers and/or maintenance personnel are relied upon to dose systems with bottled additives. This paper will detail the development and testing of a solution to the problem of unreliable additive addition in the field, a fuel filter that consistently releases a lubricity enhancing additive into fuel systems. The filter will be shown to have consistent release and effective performance through a variety of laboratory and field evaluations that will be detailed in this paper.

Inconsistent fuel filter life is a problem that continues to plague most heavy-duty diesel fleets. It has been proven that fuel filter life can be strongly influenced by the thermal and oxidative stability of diesel fuel that is being filtered. Filters consistently exposed to diesel fuels that produce a tar-like substance in abundance upon heating (sometimes termed “asphaltenes”) will plug far more rapidly than filters exposed to diesel fuel that does not easily form these tar-like substances. Fuel additives have long been used to maintain fuel system cleanliness and to improve diesel fuel stability. It follows logically that such additives could have a positive impact on fuel filter life by maintaining the cleanliness of the fuel filtration media. This paper reviews the laboratory evaluations and field tests that were run to compare fuel filter life in both the presence and absence of diesel fuel additives.

A three-pad dip-and-read test strip has been developed for determining whether the pH, chloride and sulfate levels in engine coolant samples lie within or exceed the recommended ranges. The preferred ranges are 7.5 to 11.0 for pH, below 200 ppm for chloride ion, and below 1500 ppm for sulfate ion. Conditions outside of these limits can lead to corrosion of engine cooling system metal surfaces. A quick and convenient test can determine whether the coolant is suitable for continuing use or should be drained from the system. Extensive performance and stability evaluations of the test pads have been carried out, to ensure that the test strip results agree with reference method results and that test strips are stable under normal storage and use conditions. The test strips were evaluated with different glycol levels, with both ethylene and propylene glycol samples, and under different lighting sources.

A test method that will age coolants in a manner representative of coolant aging in the field is vital to the development of coolants that meet expected performance criteria. In an attempt to develop such a test, two approaches were taken. A phosphate buffered, molybdate/nitrite containing, propylene glycol based, heavy-duty coolant was aged in the laboratory using both a flow stand and a reflux apparatus. Samples of the coolant were taken at various time intervals during both tests. The samples were analyzed to determine glycol degradation product, sulfate and corrosion product accumulation, additive depletion, and pH changes. The results were compared to actual field results for the same coolant to determine which of the two approaches best simulated coolant degradation in the field. The flow stand appeared to best simulate actual field results.

A test strip containing three pads for measuring the freezepoint protection, molybdate and nitrite levels in heavy-duty diesel engine cooling systems has been developed for commercial use. The test strip requires no pretreatment or dilution of the sample, other than to allow it to cool to 130 degrees F or lower, and gives results for all three tests within two minutes. The test results are sufficiently accurate, and the strips are stable over extended periods of time, provided the container is kept tightly closed and away from direct sunlight and prolonged elevated temperatures when not in use. The freezepoint test offers an inexpensive alternative to refractometers. Since it can be used with either ethylene or propylene glycol coolants, it is recommended over the use of hydrometers.