Before every oil refiner in America comments negatively on the title of this article, allow me to clarify that nearly all of the diesel fuels produced by today’s refineries for sale into the marketplace “do” meet the required ASTM D-975(1) Specification for diesel fuels. Unfortunately, the current diesel fuel specification has various short-comings relating to older engines as well as today’s newer technology common rail fuel injection engines.
Add to that the fact that some diesel fuels sold today are not composed solely of the pure diesel fuel as originally refined. This is true because many originally manufactured diesel fuels are mixed and blended with other diesel fuels prior to finding their way into the fuel users’ tanks.
Blending No. 2-D diesel fuel with lighter distillate No. 1-D and/or kerosene is a common practice conducted by refiners, intermediate terminal storage facilities as well as fuel suppliers and distributors during the cold weather months in North America. While many believe this is a viable method of reducing winter fuel operability issues, it is not the best winterization technique for the end fuel users because it is very expensive (for customers) AND it changes the physical parameters of the original pure diesel fuel product.
While, these changes may appear as a positive for the fuel supplier, they most often are negatives for the fuel user because these fuel supplier actions cost the consumer more money and provide fuels with poorer physical fuel components for the engines to burn. Less than satisfactory diesel fuel physical properties during the winter months result in changes to the fuel distillation temperatures lowering fuel BTU energy contents so the engines will consume more fuel to accomplish the same amount of work needed to be done.
Finally, while these less than optimum diesel fuels will burn and drive the diesel powered vehicle down the highway (or across the expanse of the property site), just moving the equipment may not be acceptable to the driver. With lower power production, the driver unconsciously tries to make the equipment perform as expected by increasing throttle settings and shifting into a lower gear number for more power output. Both of these reactions increase fuel consumption and raise operating costs for the equipment owner.
If however, the diesel fuel “IS” of the right quality and specification and the engine does produce the proper horsepower, no deliberate operator reaction is required to achieve diesel equipment performance and costs are optimized.
What Is Wrong With Today’s Diesel Fuels
It is a well-known fact that changes in diesel fuel and diesel engine technology in Europe happen years ahead of the United States. Therefore, most of the chemical additive improvements to ‘fix’ diesel fuel and enhance diesel engine performance for the last fifty years have their roots in Europe. These facts should be expected since Europe transitioned to diesel fuel power many years before the United States while America predominantly traveled the gasoline powered developmental road until this past decade.
The biggest problem with today’s diesel fuels in America stems from the fact the diesel engines today need much higher performance parameters than are actually produced in diesel fuels in North America. USA diesel fuel product specifications and performance have not kept pace with diesel engine developments.
This situation is the result of the heavy influences of major oil (fuel) producers within ASTM and the compromises instituted in ASTM diesel fuel specifications made to appease these petroleum refiners. This statement is not to imply there is no equipment manufacturers’ representation or actual fuel users within ASTM, but only to point out that in most cases, when changes to the ‘required’ fuel quality specifications are discussed, the influence of petroleum producers generally is what carries the most persuasive weight.
LET’S TALK SPECIFICS:
The newer Common Rail Fuel Injection (CRFI) diesel engine systems are designed with component parts that have extremely small tolerances and these systems operate with exceptionally high pressures. CRFI systems designed since 2007 cannot tolerate even the smallest amount of fuel contamination (or water) and they must be kept exceptionally clean and properly lubricated at all times.
These two conditions (fine tolerance parts and enormously high operating pressures) demand better quality cleaner diesel fuels with increased Detergency and improved Lubricity values. Unfortunately, the ASTM D-975 Diesel Fuel Specification does not include a Detergent requirement and the current Lubricity specification (520μm maximum HFRR(2) wear scar) has not been upgraded since 2007 to achieve today’s necessary Lubricity protection. Diesel fuel producers refuse to voluntarily provide (incorporate) available fuel additives that would protect CRFI engines. Unlike Europe’s mandates, the USA Government does not legislate consumer protection directives regarding diesel fuels.
Additionally, the ASTM D-975 Specification parameter for fuel combustibility (Engine Cetane Number) has not been changed in over fifty (50) years! Despite the fact that the European diesel fuel specification has been constantly upgraded over time to today’s mandated 51+ minimum. Even though Europe is expected to mandate a 55+ in 2018 or 2019, the USA specification is stagnant and requires only a “minimum 40”.
The current low Engine Cetane Number specification situation in America is more economical and profitable for the refiners and diesel fuel suppliers while the fuel consumer’s needs are neglected. Today’s high performance engines demand higher Engine Cetane Numbers in order to provide optimum combustibility and maximum fuel economy with minimal unwanted fuel related emissions.
Another subject area missing in the current ASTM D-975 Specification for diesel fuel productions is the lack of definition of Storage Stability and Deposit Modification. While these two topics are difficult to define, they should be seriously addressed. It is a known fact that after refining diesel fuels (as organic hydrocarbons) naturally degrade over time. This process of oxidation degradation leads to an increase in fuel system deposits (free carbon particulate, tank sludge and varnish formations are three of the most common traits).
None of these common occurring conditions are good for the CRFI engines or the pre-2007 diesel engines and all will cause major operability problems for the diesel equipment operator. Again, while there are available fuel additive chemistries to properly stabilize and protect diesel fuels during long-term storage and eliminate (or greatly minimize) fuel related deposits, nothing (to the author’s knowledge) is being done at ASTM to mandate incorporation of such solutions into the ASTM D-975 Specification.
Finally, although ASTM has attempted to address winterization of diesel fuels, the solutions written into the ASTM D-975 Specification fall short in many areas when really frigid weather occurs (especially with regard to keeping the paraffin Wax Suspended during cold temperatures).
Although the ASTM D-975 Specification attempts to help the diesel fuel user with ‘suggestions’ for winterization testing, nothing (other than a complicated 10 percentile temperature discussion) is done in the Specification to mandate the fuel producers or fuel distributors to provide fuels that would guarantee operability for the buyer’s equipment during expected winter applications.
This is especially true with diesel fuels containing unusually high amounts of moisture (i.e. more than 150ppm of water) despite the fact that the current ASTM D-975 Specification allows 5000ppm of water and sediment to be delivered in the fuel. It should be noted that one of the biggest problems with CRFI engines is the salt deposits that build up internally in the fuel injectors from the typical moisture content, usually less than 150ppm, found in today’s diesel fuels.
There are solidly proven winterization chemical additives (including effective moisture de-icer agents) that can be incorporated into diesel fuels at very economical costs in order to guarantee winter operability at cold ambient temperatures in North America. Unfortunately, ASTM refuses to mandate their use and the solution is left to the marketplace to sort out with absolutely no policing of the marketed claims of the individual fuel additives offered for sale to the public.
This has led to an enormous amount of fuel additive ‘marketing fluff’, misrepresented claims, exaggerated performance benefits and bold faced lies presented to the diesel fuel buyer. This leaves a bad taste in the fuel additive buyer’s mouth and distrust of even the legitimate diesel fuel additive supplier.
What Can Be Done by ASTM International to Fix The Problem?
While it is understood that the scope of ASTM International’s responsibilities does not necessarily include the mandating of any specific fuel additive company’s products, the ASTM organization “could” require stronger language within the ASTM D-975 Specification that would encourage the diesel fuel user to use diesel fuel additives that properly correct the deficiencies within the ASTM D-975 Specification.
Along with such encouragement language regarding effective performance improving diesel fuel additives, ASTM International “could” admit that the ASTM D-975 Specification does have limitations with regard to guaranteeing the most efficient and proper operation of diesel engines during all types of weather conditions.
Additionally, ASTM International “could” strongly recommend the diesel fuel user TEST the prospective fuel additives in order to verify the marketing claims BEFORE purchasing these products.
What Can The Diesel Fuel Buyer Do to Fix The Problem?
There are quality formulated fuel additive chemical products that can correct nearly all of the short-comings of most diesel fuels offered for sale in North America and around the world. The diesel fuel buyer just has to look for them and be diligent about investigating, testing and verifying the performance claims made.
All legitimate diesel fuel additive suppliers will provide product samples for testing to prospective customers. The diesel fuel buyer should then have an in depth laboratory testing program set up with a qualified petroleum laboratory testing facility (one that specializes in and has experience in ASTM D-975 Specification testing) to prove or disprove the marketing claims made by the fuel additive supplier.
Again, this detailed laboratory testing should be done BEFORE buying any diesel fuel additive product(s). This laboratory testing should also be done on more than one specific unadditized base diesel fuel (at a minimum two different fuel samples with varying Cloud Point(3) temperatures) should be tested) and ideally on the diesel fuels the fuel additive buyer expects to use in his equipment.
Here is a list of some of the physical property improvements the diesel fuel buyer should be looking for to enhance the quality and performance of the diesel fuels purchased:
(a) Cetane Improver to increase the Engine Cetane Number to 50+
(b) Detergent chemistry to achieve a DW-10 Detergency Rating in all fuels
(c) Lubricity Agent to lower the HFRR fuel lubricity to 400μm or less
(d) Storage Stability to slow natural fuel degradation for 12 months or more
(e) Deposit Modifier to clean off existing deposits and minimize future fuel related deposits
(f) Cold Flow Improver to lower the Cold Filter Plugging Point (CFPP) by 25 degrees F or more
(g) Wax Dispersant to fully suspend the paraffin wax 25 degrees F below the Cloud Point
(h) De-Icer Agent to reduce the moisture freeze point to – 40 degrees F or more
Each of the above physical parameter improvements CAN be achieved with the ‘right’ diesel fuel additives available today. These performance improvements can easily be achieved with the ‘right’ chemistries in the ‘right’ concentrations when treated at the ‘right’ dosage rates in the diesel fuels purchased.
If the ‘right’ chemistries are compounded and treated correctly, more than 90 percent of all diesel fuel combustion issues and nearly 90 percent of all unburned hydrocarbon and related emissions at all operating levels will be eliminated. The other 10 percent can be directly targeted by specific chemicals compounded into specialized diesel fuel additive products for the individual application.
The diesel fuel buyer (consumer) must be proactive before the fuel purchase and not reactive to the fuel problems after the fuel is being used.
Finding the ‘right’ diesel fuel additive(s) is not easy, but the rewards of less fuel related maintenance headaches, a cleaner environment, longer equipment life, reduced driver complaints and much better fuel economy/efficiency (fuel savings) are more than worth the effort. These benefits will pay significant dividends for many years into the future.
(1) American Standard for Testing of Materials specification for diesel fuels (now known as ASTM International)
(2) HFRR – High Frequency Reciprocating Rig Test
(3) Cloud Point is the temperature at which the liquid paraffin in the diesel fuel begins to change into a solid wax material