Diesel exhaust fluid different

As of this month, all new diesel engines from 175 to 750 horsepower must be Tier 4 compliant, which means diesel exhaust fluid (DEF) will be required to meet the criteria.

From now on, every new implement will need DEF to function. Unlike previous emissions systems since the 1990s, there is no way to circumvent Tier 4 technology. There are no aftermarket chips or under-the-counter controllers to free an engine of the DEF requirement.

Another significant change from previous fuel systems is that DEF has virtually zero tolerance for contaminants. The ISO standard 22241 sets out the criteria for DEF purity.

It takes only 0.1 teaspoon of copper, zinc, chromium or nickel to turn a 5,000 gallon DEF tanker into 5,000 gallons of worthless liquid. At the higher end of the contamination continuum, a mere 2.3 teaspoons of potassium will ruin 5,000 gallons of DEF.

There is no leeway for contamination. Farmers who already operate DEF equipment have learned that cleanliness really is next to godliness when it comes to handling this temperamental additive.

Sensors feeding into the engine control unit detect any glitches in the DEF system, and the ECU begins to shut the engine down if the DEF flow falls below a certain point. Dealers say there is no way to fool the sensors.

Five things can happen if the purity of the liquid is compromised:

  • Consumption of the expensive liquid escalates.
  • The engine shuts down in the field.
  • Contamination causes the selective catalytic reduction (SCR) process to malfunction.
  • The SCR and other systems can be severely damaged.
  • The engine manufacturer can void the warranty.

“We’ve already seen a number of situations where the engine manufacturer has voided a warranty be-cause of contaminated DEF,” said Lorne Van Wyk, head of research and development at Thunder Creek Equipment in Iowa.

Thunder Creek specializes in service trailers for farmers and construction. Because its trailers supply diesel to these clients, the company began developing ISO 22241 compliant DEF handling systems long before the 2014 mandate went into effect.

“This is a serious matter. It’s a whole new ballgame and we can’t take it lightly. DEF must be kept chemically pure because of the way it splits molecules,” Van Wyk said.

“If DEF is contaminated, it just does not work. It can plug the DEF injection. Not only does that impact the emissions into the atmosphere, it also disables and possibly ruins the system. Now, put yourself in the place of the engine manufacturer. If the technician comes out to your disabled model 2014 tractor and finds that the system needs replacement because of contaminated DEF, the manufacturer is not going to replace it under warranty. It’s $4,000 or $5,000 out of your pocket.”

Thunder Creek’s R & D department does a lot of work directly with farmers. For example, Van Wyk said it had a classic case of a plugged injector on a brand new tractor this spring.

“The tractor would run fine for about an hour and a half, then it would go into the safety mode and drop down to 1500 rpm,” he said.

“The operator would shut it down and wait for an hour, start it up again and work for another 90 minutes or so. This went on over and over and the dealer couldn’t figure it out. I finally figured out that small bits of plastic had been left in the tractor’s DEF tank from the factory. When the engine ran, it would suck the bits up to the filter and plug it up enough to throw the engine into the safety mode. When you shut the engine down, the injection pump automatically does a backwash. That backwash would send the plastic bits back down into the DEF tank. Once we removed the tank and cleaned it out, the problem was solved, and it’s been fine since.”

Van Wyk said no DEF component leaves the Thunder Creek factory until it’s been thoroughly cleansed with de-ionized water, which is the main component of DEF. The goal is to ensure that no implement experiences down time because one of the company’s trailers contaminated a DEF system.

“Farmers only operate their equipment when they have a small window of opportunity. That applies to seeding, spraying, swathing, combining, manure application and everything else,” he said.

“Every one of those operations has a bushel impact and a dollar impact. An engine shutdown can have a seriously detrimental impact on the bottom line for the year. Everything we do is aimed at eliminating DEF from the list of possible things that can go wrong.”

Van Wyk said Thunder Creek has developed an air-tight closed loop circuit for transferring DEF from one container to another. It is most commonly used to transfer from a DEF tote in the field to the implement.

It is completely isolated from the atmosphere, which eliminates virtually all chances of contamination during pumping operations. The closed system also prevents evaporation of the fluid, which is comprised mainly of water.

The two-way pump is an important component within this closed loop. Once the implement DEF tank is filled, the same pump is reversed to do a back wash, which flushes residual DEF from the nozzle and hose back into the tote.

The urea in DEF has a much higher purity than the urea in agricultural fertilizer. Because of the highly corrosive nature of DEF, Thunder Creek uses 304 grade stainless steel and ethylene propylene domineer steel where corrosion might be a factor.

The high water content makes DEF susceptible to freezing, which can cause a container to burst open. Thunder Creek’s response was to offer optional tank heaters for its containers. It also manufactures all tanks with sloped sides so the ice will push up instead of out if it should happen to freeze, thus preventing the container from splitting open.

For more information, contact Lorne Van Wyk at 866-535-7667 or visit www.thundercreekequipment.com.

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