By Mike Whalen
In spite of the current use of alternate fuels, it seems to me that the vocational markets, particularly construction, forestry, agriculture, utility, oil and gas and mining exploration, will be using diesel fuel well into the future.
It would not be practical – read cost effective – for a fleet to provide multiple re-fuelling facilities at each of their operating locations to cover the needs of the mixed fleet of vocational trucks and equipment.
This is the time of year diesel fuel is formulated for winter operations. And providing ‘clean’ fuel to your diesel engines is the main objective to keep diesel engines operating at peak efficiency throughout the winter.
It is obvious that particulate (dirt) must be removed from the fuel delivery system. But, in the winter, water in diesel fuel can have a major impact on smooth trouble-free operations for those in the tough vocational markets.
Regarding regular fuel filters, filter manufacturer, Donaldson Company says: ‘The published micron rating, (or particle size that a filter captures), does not provide an understanding of the performance of the filter unless you also know the efficiency at which it is measured. The efficiency of a liquid filter on a given particle size is frequently described as either a Beta ratio (ß), or as a percentage (%). Two filters that both claim to capture the same size particles or have the same micron rating may provide vastly different performance results. For example, when comparing two filters that are both rated at 5 microns, if filter A has an efficiency of 99% it will remove 99% of contaminant 5 micron and larger from the fluid. If filter B has an efficiency of 50% it will only remove 50%, or half, of the same contaminant from your fuel. Filter B may allow up to 50 times more contamination to pass than filter A, a very different level of performance!’ www.donaldsontoolbox.com
It’s important to understand that the most important contaminant in diesel fuel is ‘water’! Water reduces the ability for fuel system components, pumps, injectors, etc., to be lubricated properly and will assist particulate scoring that, in the case of injectors, will cause a disruption of the spray pattern of the fuel. This means fuel will not burn efficiently and allow un-burned fuel to be returned to the fuel tank. The result is increased fuel consumption and a reduction in power.
Today’s ULSD (ultra-low sulphur diesel) fuels reduce the natural lubricity of diesel fuels that is necessary for the operation of pumps and injectors. Water in fuel has a major impact on the lubricity of today’s low ULSD fuels.
It therefore becomes increasingly important to remove the water and replace the lost lubricity. This can be accomplished with a combination of filters, with water removal capabilities, and a fuel additive to add lubricity.
Years ago, before ULSD, I was talking to a bulk fuel delivery wholesaler in central Ontario. I suggested they could get a leg up on their competitors by installing a water separator that coalesces water from the fuel as it is pumped from the tank to the truck or from the fuel truck to the fleet’s storage tanks. He answered, “But, who will pay me for the water I bought with the fuel?”
As a further test we used a tool that could measure the amount of water in the tank and dipped a tanker that had been parked for awhile. We measured about two inches of water that had accumulated!
On another occasion we were asked by a transit bus authority to check their in-ground tanks for water. Their buses were having trouble with water in the fuel and we were looking for the source. It was suspected that a recent heavy rain storm had caused water to accumulate over the area in the yard that contained the filling points for the underground storage tanks.
To determine if this was the case, we installed a water coalescer on a fuel pump and started refuelling the buses as they returned from a run. We were able to keep the water collection bowel’s drain cock open to drain the water that was being collected while we refilled the buses. Amazing!
Diesel fuel handling, storage and delivery systems, all contribute to water in fuel. Water can enter underground tanks through deteriorated tank walls or down the filler tubes. Changes in atmospheric temperature can cause condensation to form on tank walls and accumulate in the bottom of the tank.
Two classifications of water are present in fuel – Free Water and Emulsified Water. Free Water is visible in large droplet form or as a layer found in the bottom of the fuel tank. However, once vibration or movement occurs in the fuel system, Free Water is broken down into tiny particles and emulsified, or mixed, with the fuel. Passing fuel through a pump also breaks down – or emulsifies – free water into tiny, almost invisible, particles. The use of a coalescer is the only way to remove emulsified water
Both free water and emulsified water should be removed from the fuel supply.
Keep the water out!
With the use of ULSD and the loss of its lubricating quality, water contamination is the most important factor to look for in diesel fuel.
The diesel injection system is made up of precision components with extremely close tolerances that rely completely on the diesel fuel for lubrication. Water will hinder diesel fuels’ ability to lubricate the pump and injectors. Injectors that are scored by particulate carried in the fuel or corroded can also degrade the fit and allow fuel to drain along the injector barrel wall into the cylinder.
When selecting components to keep your fuel system running at peak efficiency 1) select a primary filter to take care of the coarse particulate, 2) a secondary filter for fine particulate. You filter supplier can help you decide between a full-flow or combination full-flow by-pass system.
Also, add a fuel – water coalescer after the secondary filter. There are various combinations of filters and water coalescers on the market. A supplier that specializes in servicing fuel systems can provide excellent advice. www.diesel.org.
Sitting water in the fuel system can result in biological growth – or gelling. To reduce the fuel from gelling use a fuel heater and an additive. The fuel heater can be in-line or acquired as part of the filter/coalescer assembly.
An approved additive replaces the much-needed lubricity missing from ULSD in a way that protects all critical fuel system components such as fuel filters, fuel lines, injectors and fuel pumps by not allowing the fuel to change viscosity and deliver the fuel as originally intended by the engine manufacturer.☚