DEF (Diesel Exhaust Fluid) is a non-hazardous mixture of 32.5 percent urea and 67.5 percent deionized water. DEF is sprayed into diesel vehicles’ exhaust streams to break down harmful NOx emissions into harmless nitrogen and water. Selective Catalytic Reduction (SCR) is a system that can be found on 2010 and later model year vehicles, as well as many diesel pickups and SUVs. DEF isn’t a gasoline additive, and it’s never mixed with diesel. It’s kept in its own tank, usually with a blue filler cap.
Is diesel exhaust fluid necessary?
As if finding a clean spot to pump gas wasn’t difficult enough, diesel owners also had to worry about keeping their diesel exhaust fluid (DEF) tanks filled off. What happens if the treatment tank is completely depleted? We did the research and testing so you don’t have to.
Diesel veterans have long known how to deal with this issue. The following primer is intended for newcomers to diesel engines as well as gasoline-engine fans interested in learning more about life on the other side. DEF, commonly known as AdBlue or Blue DEF, is an elixir required to ensure that the exhaust from a diesel vehicle is as pleasant as an Alpine breeze. Those who refuse to listen to DEF risk severe consequences.
DEF is a fluid made up of urea and deionized water in a 1:2 solution that can be purchased at most service stations for $6 to $10 a gallon. To manage some pollutants, it’s stored in a reservoir separate from the gasoline tank and metered into the engine’s exhaust stream. The DEF vaporizes and decomposes into ammonia and carbon dioxide inside the exhaust pipe. Inside the vehicle’s selective catalytic reduction (SCR) catalyst, these two chemicals react with oxygen and harmful nitrogen oxides. Nitrogen, water vapor, and carbon dioxide are produced as a result of this process.
Make certain that any DEF you buy is labeled to meet ISO (International Organization for Standardization) 22241 requirements. While DEF does not deteriorate with age, it can freeze, so keep your supply somewhere warm. Because the contents stay in solution, no shaking or mixing is required prior to use.
What is diesel exhaust fluid used for?
We get a lot of questions about DEF and how to use it effectively on your forecourt, so we asked the expertise of Danny Seals, a forecourt solutions expert, to provide us with some simple answers.
What is DEF?
DEF is a urea-water solution that is injected into the exhaust stream of diesel automobiles to convert NOx gases (harmful emissions) into nitrogen and water. Vehicle manufacturers introduced a Selective Catalytic Reduction (SCR) technology to meet EPA emissions limits in 2010. This is a strategy to achieve the requirements without sacrificing engine performance or fuel economy. DEF isn’t a fuel additive, and it’s kept in its own tank.
Who needs DEF, why?
DEF is required for medium and heavy-duty vehicles equipped with diesel engines manufactured after 2010. To meet emissions rules, the vehicle is configured to inject DEF into the exhaust stream. The engine performance will be diminished and lower speeds will be imposed if the vehicle is allowed to run out of DEF.
What are the different delivery modes of DEF?
DEF is available in a variety of forms. A driver can purchase jugs/containers in a variety of sizes. This necessitates the driver physically transferring the DEF into the car. When installed, DEF can also be dispensed into the vehicle using a fueling dispenser.
Which retailers should offer DEF and what indicators can they use to decide?
Because there is such a vast population of automobiles on the road, DEF is an excellent product for all c-stores to offer. Retailers who sell diesel at their gas stations can utilize the volume sold to estimate the number of diesel customers they have. DEF is required by the majority of today’s heavy-duty trucks. Locations with a separate large truck filling station might think about putting DEF in the dispensers. Because they buy DEF in quantity to keep in their tanks, this results in higher profit margins. Some places that sell a lot of diesel on their forecourt should also consider a dispenser option.
How can Gilbarco help retailers get into DEF?
Since the inception of DEF requirements, Gilbarco has been the industry leader in DEF dispensers. Over the years, we’ve worked with large stores to provide dispenser functionality, and we’ve established the industry standard for this service. Gilbarco assists merchants in entering the DEF dispensing market by providing factory-installed options and retrofitting existing dispensers where DEF is stored in bulk.
What happens if you run out of DEF?
Vehicle makers must implement procedures to ensure that vehicles cannot run without Diesel Exhaust Fluid, according to the US Environmental Protection Agency (DEF). The driver of a vehicle receives a succession of alerts on their dashboard displays before the DEF tank runs out (much the same way as if they were running low on diesel). In general, an amber warning bulb will illuminate when the DEF tank level drops below 10%, flashing at 5%, and solid amber warning light will illuminate when the DEF tank level dips below 2.5 percent.
The engine’s power is lowered, a solid red warning is displayed, and the vehicle’s speed is limited to 5 mph until the DEF tank is refilled if the truck is allowed to run out of DEF.
How much does DEF cost?
The Clean Air Act of 1970 paved the way for the creation of the Environmental Protection Agency. The Environmental Protection Agency (EPA) has been constantly evolving and enacting laws to address the country’s environmental requirements for 46 years. For many years, owners of three-quarter and one-ton light-duty pickup trucks were not required to install additional smog equipment. All of that changed in 2008, when the Environmental Protection Agency mandated the use of diesel particulate filters on all three-quarter-ton and larger vehicles, as well as biannual smog testing that included a visual assessment of the truck to ensure the DPF parts were still there. The rules were tightened even more in 2010.
Many people believed that the age of enormous power and torque was finished, and they resolved to never buy another vehicle. However, something fantastic occurred, as well as the polar opposite. Americans have proven to be adaptable and resilient. Every manufacturer worked out a way to reduce NOx emissions while still producing more horsepower and torque than ever before. Strife yields bread, and bread yields innovation.
The application of selective catalytic reduction was the engineering breakthrough. To break down the created NOx into harmless nitrogen and water molecules, the great majority of these systems use diesel exhaust fluid (a mixture of urea and deionized water) injected into the exhaust system. Since the introduction of DEF (Diesel Exhaust Fluid), also known as after-treatment technology, in the exhaust, the manufacturer is free to create as much power as they like. The DEF is kept in a separate tank that is insulated and heated, with a blue filler cap to identify it.
Despite the effort around technology breakthroughs, there are still two factions of diesel guys out there: those who have accepted the EPA modifications and those who are still adamantly opposed to any limits. There has been a transition to older used diesel engines or remanufactured diesel engines that have been grandfathered in for individuals who are unable to accept the modifications. The purpose of this essay is to lay forth the cold hard facts concerning DEF and to educate the public on how to make better diesel operator decisions.
What exactly is Diesel Exhaust Fluid (DEF)?
DEF is a mixture of 67.5 percent deionized water and 32.5 percent urea from a chemical standpoint. Urea is a nitrogen chemical that, when heated, converts to ammonia and is employed in a range of industries. Although urea is technically produced from a urine waste, it is synthesized for mass manufacture. The American Petroleum Institute regulates most DEF products. Let’s look at the science of DEF in combination with exhaust. DEF is made up of two parts: (NH2)2CO and (NH2)2CO. When injected into hot exhaust gas, the water evaporates, leaving ammonia and isocyanic acid.
STEP 2: With water, the isocyanic acid breaks down chemically into carbon dioxide and ammonia:
STEP 3: At this step in the chemical reaction, ammonia will decrease nitrogen oxides in the presence of oxygen and a catalyst:
2(NH2)2CO + 4NO + O2 = 4N2 + 4H2O + 2CO2; 2(NH2) 2CO + 3NO2 = 7/2N2 + 4H2O + 2CO2; 2(NH2) 2CO + 3NO2 = 7/2N2 + 4H2O + 2CO2; 2(NH2) 2CO + 3NO2 = 7/2N2 + 4H2O + 2CO2; 2(NH2) 2CO + 3NO2
How Often Do You Need To Fill Up the DEF Tank?
This is a question that is specifically dependent on the diesel truck’s MPG and usage. The usual average light duty truck will require 2-3 gallons of DEF per 800 miles, regardless of the load, according to the OE manufacturer. Most new trucks with an average miles per gallon rating of 20+mpg, on the other hand, will travel 8,000-10,000 miles on a tank full of DPF (10 gallons). Each vehicle is different; for example, a Dodge Ram has a gauge that shows how much DEF is left in the tank, while a GM truck has a digital readout and a Ford truck has a basic low DEF indicator.
Fuel models for medium and heavy duty trucks will vary, but DEF usage will be around 2% of total fuel consumption, according to Cummins Filtration. One gallon of DEF is used for every 50 gallons of diesel fuel used. Here are some forecasts from our friends at Cummins Filtration for Medium and Heavy Duty Consumption:
Where can you buy DEF?
Don’t be tricked by thinking that DEF can be purchased just about everywhere. DEF is typically sold in large bottles holding numerous gallons of the substance at truck stops. If you’re in a pinch, some petrol stations will have DEF, but don’t bank on it. It is critical to note that if you do not refill an empty DEF tank, the engine will shut down automatically. Because DEF isn’t offered everywhere, you don’t want to be trapped anywhere with an empty tank. TravelCenters of America, Walmart, Target, Love’s Travel Shop, SAPP Brothers, Flying J Truck Stops, Petro Stopping Centers, and Pilot Travel Centers, O’Reilly’s, NAPA, and Advanced Auto are all common places to buy DEF. We’ve also put together a list of the most popular DEF manufacturers.
What are the Pros and Cons of a DEF Truck?
DEF has few drawbacks because it is a relatively straightforward technique. However, because the Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR) are prone to clogging, they can cause a slew of maintenance and repair concerns. These systems are intricately designed, and even a simple blocked filter can result in pressure and temperature differentials that influence the engine’s overall performance.
The only disadvantages of DEF are the higher initial cost, added weight, and the need for more storage space for an extra gallon of the fluid. Better fuel economy, more horsepower, more optimized combustion, fewer regeneration troubles, less engine wear, and it only emits nitrogen and water vapor into the air are some of the benefits.
Is emissions production really an important issue?
Whether it’s a major concern or not is debatable, given that all light-medium diesel engines built after 2008 must meet with EPA regulations. Smog, greenhouse gas emissions, and acid rain have all been linked to NOx emissions. The DEF converts NOx into pure nitrogen and water vapor as part of the Selective Catalytic Reduction system (SCR). Climate change is a contentious issue, but we can all agree that adding additional gasses to the atmosphere of any kind isn’t something we need.
Will DEF Lower My Fuel Mileage?
It is natural to believe that any EPA-mandated alterations to the diesel engine will be detrimental, but this is not the case. The big diesel makers learned that they could fine-tune the engine in whatever way they wanted, then let the SRC and DEF remove the particles. The engines are designed with performance in mind first, and then the SRC, DPF, and DEF are added as an afterthought to remove what is no longer required. Manufacturers have discovered that engines with SCR technology achieve better fuel mileage than engines with conventional internal pollution reduction systems. Fuel fed to the SCR provides an additional supply of components to burn. It is possible to increase fuel mileage by as much as 5% to 7%.
Has this new DEF Technology Ever Been Used Before?
DEF technology has been employed in agriculture, industry, and large-scale power generation in the country for decades. The premise is the same everywhere: urea combined with heat produces ammonia, which induces a chemical reaction that reduces NOx by 70% to 95%. In fact, nitrogen-released fertilizer accounts for 90% of urea production. It’s worth noting that automotive-grade urea has a far higher purity level than fertilizer-grade urea. If a lower-grade fertilizer, urea, is used in vehicle engines, the SCR may disintegrate, causing the engine to fail. It could even cause ECM sensors to issue an inaccurate DEF Tank Empty signal.
Does DEF Evaporate After A Period of Disuse?
Yes and no are the answers. With the valves wide open, the temperature at which DEF combines with NOx exhaust immediately out of the cylinder head is between 1400-1600 F. The chemical reaction occurs at substantially higher temperatures than those experienced on a hot summer day. For example, converting the DPF to ammonia and evaporating it would take two years at a steady temperature of 125 degrees F. However, because DEF is roughly 2/3 water, any temperature above 86 F risks some evaporation. Unless exposed to consistent hot climes, you won’t have to worry about a gallon or two of the stuff going bad or evaporating from inactivity.
Is DEF a Toxic and Harmful Chemical?
Urea, the active element in DEF, has been chemically produced since 1828, when German chemist Friedrich Wöhler used ammonium chloride to treat silver cyanate. Herman Boerhaave, a Dutch chemist, was the first to detect urea in urine in 1727. Urea is mostly employed in agricultural fertilizers, but it is also found in the chemical industry, explosives, lotions, skin creams, hair removers, plastics, dish washes, and fuel cells. Humans are not extremely poisonous to urea and, as a result, DEF. Urea can irritate the eyes, skin, and respiratory tract, but it is not dangerous. High quantities of urea in the blood can be dangerous to humans, however absorption of modest doses of urea, when accompanied by proper water intake, is not. In nature, urea can induce algal blooms, which can produce harmful fumes when it decomposes over its melting or heating threshold. When nitrites are mixed with certain oxidants, such as chlorides, they can create fires or even explosions.
What happens to the engine if the DEF Tank is empty?
The EPA now requires all diesel engine manufacturers to include a tiered warning system (internal gauges on the dash) that tells the driver how near the DEF tank is to being empty. The truck will stop working if you ignore the DEF warning. Some diesel engine manufacturers allow the engine to go into low-power mode, allowing the truck to “limp home” or limiting the number of times the engine can be turned over. However, the diesel engine would eventually fail to start. Treat the DEF tank as if it were a fuel tank; you don’t want to be stranded somewhere because you forgot to replace it.
Does DEF Have a Low Freeze Point?
At 12 degrees Fahrenheit, the normal 32.5 percent DEF solution begins to crystallize and freeze. When urea and water are combined in DEF, they both freeze at the same time. This is advantageous to the user because the DEF solution does not get diluted or too concentrated as the fluid thaws. The product’s grade is unaffected by freezing and thawing cycles. When DEF is frozen, it expands by 6.5 percent to 7% by volume. Freezing periods are accommodated by the packing.
What is the best method to keep DEF from freezing?
Keeping a gallon or two of DEF in your vehicle is totally safe, but it is not recommended. At 86 degrees Fahrenheit, DEF begins to degrade. It’s all too easy to forget about the DEF in the rear of your vehicle, and given enough hot days, the fluid can become unstable and degrade, but at a very slow rate. A diluted DEF without the 32.5 percent urea combination can be harmful to DEF and SCR, however this is a rare occurrence. As a result, on exceptionally cold days below 12 degrees Fahrenheit, DEF will freeze in the DEF tank. This is totally normal and will have no negative impact on the engine. The SCR systems are intended to give heat to the DEF tank, allowing the tank and related supply lines to thaw quickly.
Can I add anti-freezing solution to the DEF mixture to keep it from freezing?
DEF has a relatively specific formula consisting of 32.5 percent urea and water, but it also contains additional compounds in trace amounts to help stabilize the product. The precise chemical makeup of the mixture would be disrupted by an addition, lowering the NOx reduction characteristics. The DEF mixture’s ability to function effectively will be jeopardized by further blending, and the SCR system will be harmed.
How is the production of DEF regulated and can I make my own?
It is not advisable for direct consumers to make their own DEF. DEF is strictly regulated, has stringent standards for chemical purity, and comprises chemicals that are critical to the SCR system’s operation. DEF must be utilized with SCR systems and meet all ISO norms and API requirements, according to Caterpillar, Cummins, and Detroit Diesel, among others. The American Petroleum Institute (API) has a wholly voluntary program that confirms the chemical purity of DEF and that manufacturers fulfill ISO requirements. API Certification is achieved by all major DEF brands present on the consumer market.
What is the shelf life of DEF?
The batch of DEF will last around two years if it is stored at ambient temperatures of 75 degrees Fahrenheit with no large periods of exposure to heat above 86 degrees Fahrenheit. If a package of DEF is heated over an extended amount of time, the fluid will last about a year.
Who are the major manufacturers of DEF Fluid?
DEF Fluid is made by a variety of companies. “Oilmen Truck Tanks,” a website, has collected a list of 13 main manufacturers. DEF is available for $2-$3 per gallon at most big truck stops, auto parts stores, and convenience stores.
How can you determine the age of a container of DEF?
A manufacturers date can be found somewhere on every DEF package. It’s most likely near the bottom of the front of the packaging. This date code will reveal the precise date the batch was manufactured, as well as the age of the DEF bottle. A laser code is inscribed on the bottle of one gallon containers. A little date code is frequently placed on the product label of larger 2-5 gallon tanks. A larger label will be put on the side or top of larger DEF fluid drums (55 gallons or more) and totes (275-355 gallons). Reading a manufacturer’s code is difficult, as each one is slightly different. The batch number is usually represented by the first digit of the date code, and the next six digits reflect the date the batch was filled at the factory.
How do you identify a DEF Filling Pump Vs. a Diesel Fuel Pump?
A number of safeguards have been put in place to prevent diesel engine fuel from being injected into the DEF tank and vice versa. “The color “green” is the standard for diesel filling stations and pumps around the world. “The color “blue” has been chosen as the symbol for DEF fluid. DEF is dispensed by a normal 19 mm nozzle, while diesel fuel is dispensed through a 22 mm nozzle. As a last line of defense, the tank cap on almost all trucks should be a “brightly colored blue” to prevent diesel from entering the DEF tank.
What should I do if I accidentally dispense diesel fuel into the DEF?
First and foremost, do not be alarmed. Second, do not start the engine under any circumstances. If you don’t start the engine, putting diesel fuel in the DEF and vice versa (DEF in the fuel tank) will not hurt it. The SCR should detect the presence of a solution other than DEF in the tank and alert the driver through the dashboard ECM readout. It’s also crucial to avoid moving the vehicle. The distribution of fuel into the lines and into the SCR might be caused by moving the vehicle. Draining the tank while the vehicle is still in its original location is the best option. If the engine is started for even a short time, diesel fuel will destroy the SCR catalyst, which is highly expensive to replace and is no longer covered by the manufacturer’s guarantee. If DEF gets into the fuel system and spreads throughout the engine, it will eventually destroy the diesel engine. The DEF is incompatible with the gasoline system lines, which corrode with time.
How often do you have to add diesel exhaust fluid?
DEF is the operating fluid for Selective Catalytic Reduction (SCR) technology, which has been employed in new heavy-duty commercial vehicles since 2010. DEF isn’t a gasoline or a gasoline additive. It is injected into the exhaust system of diesel automobiles to chemically reduce NOx emissions. DEF is a high-purity urea solution that meets ISO 22241 standards. This is the highest quality and safety standard in force, ensuring that Selective Catalytic Reduction technology functions properly. Because of the fuel economy advantages of SCR over other technologies, most engine makers chose it over competing technologies. SCR has been demonstrated to enhance total fuel economy by about 5%, according to studies.
Q1: Where can I find DEF?
A: Diesel Exhaust Fluid (DEF) is widely available at most filling stations and automotive parts retail stores because practically all diesel-powered passenger cars and trucks made since 2010 are fitted with Selective Catalytic Reduction (SCR) and require it. A DEF pump is frequently located on the fuel island at truck stops. DEF is also available at key OEM outlets, such as Cummins dealers and distributors. Your fuel provider may be able and willing to deliver DEF directly to you if you have a large enough fleet and storage capacity to justify bulk purchasing.
Cummins Filtration has teamed up with Old World Industries to become the official North American manufacturer, packager, and distributor of Fleetguard Diesel Exhaust Fluid.
Q2: What’s the shelf life of DEF?
A: The shelf life of DEF is determined by the temperature of the storage facility. DEF should be stored between 12°F and 86°F, however if kept below 65°F, the shelf life is increased to two years. To extend the shelf life of DEF, keep it in a climate-controlled location away from direct sunlight.
Q3: What happens if DEF freezes?
A: While DEF does freeze at 12 degrees F, it has no effect on the vehicle’s start-up or operation. The SCR system heats the DEF tank and pipes as the engine starts up, allowing the DEF to thaw quickly and flow to the aftertreatment system regardless of the outside temperature.
Diesel Exhaust Fluid contains 32.5 percent urea and 67.5 percent deionized water in its formulation. DEF will freeze at 12°F (-11°C) in storage or when the engine is not in use. The urea and the water both freeze and thaw at the same pace at this concentration, guaranteeing that you always have the right amount of both. SCR engines are specifically tuned for optimal performance at this ratio, which is why it’s critical to use a high-quality DEF that complies with ISO standards.
There is one operational difference to be aware of: DEF expands when frozen, just like any other water-based fluid (by approximately 7 percent). When the vehicle is turned off in cold weather, the operator should wait 60 seconds before shutting off the batteries to allow the fluid to flow back out of the hoses and into the DEF tank.
Anti-gelling additives and freeze point improvers should never be introduced to DEF since they will obstruct its capacity to function properly and may cause harm to SCR system components.
Q4: How much DEF will my equipment use?
A: DEF consumption varies based on the environment, the equipment’s operation, and the duty cycle. DEF use accounts for 3-5 percent of total fuel consumption on average.
Because most DEF fill-ups occur at the same time as diesel fuel, it’s a good idea to look at utilization from that standpoint. It’s best to simply top off your DEF tank every time you refuel. Adjust your DEF refills accordingly and consider having an extra bottle of DEF on hand if you’re driving a car that sees very little actual activity or is stored in high ambient temps when shelf life is a problem.
Q5: What happens if my equipment runs out of DEF?
A: Like a fuel gauge, all EPA 2010 engines with SCR are equipped with a gauge that displays the DEF fluid level. Furthermore, they are fitted with a set of flashing lights that warn the operator when the DEF tank is running low on fluid. Vehicle speed will be limited if the DEF reservoir is not replenished and becomes low, but if DEF is injected, the engine will resume regular speed levels. A wise precaution would be to have a top-off gallon jug of DEF on each piece of equipment equipped with an EPA 2010 engine and aftertreatment system.
Engines built before to July 8, 2011 may function differently than those listed here. For more information, contact your local Cummins agent and request Cummins Bulletin 4971316, “Driver Tips For Fire And Emergency Vehicles.”
Is diesel exhaust fluid made from pig urine?
That’s why, starting in 2010, all diesel trucks were required to have systems dedicated to putting DEF to use. Diesel Exhaust Fluid, which is made up of 32.5 percent urea and 67.5 percent de-ionized water, is sprayed into a vehicle’s exhaust system to aid in the breakdown of NOx emissions, converting them to harmless nitrogen and water. If you’re thinking to yourself, “Urea is a type of urea. You’re on the right brainwave if that sounds oddly like ‘urine.’ When a body metabolizes protein, it produces urea, an organic molecule. (We do, in fact, excrete it as pee.) However, despite DEF’s moniker, “Diesel Exhaust Fluid is really constructed of commercial-grade ureasynthetic ammonia and carbonand is referred to as “pig urine.”
To put it another way, the urea and water in DEF heat up and produce ammonia. The NOx emissions are subsequently neutralized as the ammonia breaks down. The tail pipe emits fewer harmful substances, allowing everyone to breathe a little better.
Will DEF freeze in my truck?
DEF, whether in storage tanks or equipment, can freeze and cause problems. When temperatures dip below 12°F, DEF begins to crystallize and ceases to function properly. Because of the precise ratio utilized, the entire mixture can freeze and thaw together like water and ice.
Is there a diesel exhaust fluid shortage?
You may have never heard of urea, but the chemical compound’s worldwide shortage may bring Australia’s supply chain to a halt in a matter of weeks.
The molecule, which is a vital ingredient in the diesel exhaust fluid AdBlue and a major component in fertilizer, is in low supply around the world.
The main cause of the scarcity is China’s prohibition on urea exports, which previously supplied 80 percent of Australia’s urea supplies. This is because the price of fertilizer has risen dramatically, and China wants to curb the rate of increase.
However, because urea is sprayed into the exhaust systems of modern diesel cars to lower emissions, which is a necessity for trucks, passenger vehicles, and tractors, this could inadvertently take many of Australia’s trucks off the road.
So, what is urea, and how serious is the supply chain disruption in Australia?
What does Blue DEF?
BlueDEF SCR (Selective Catalytic Reduction) systems in diesel automobiles employ Diesel Exhaust Fluid, which is a blend of high purity synthetic urea and deionized water. DEF is a chemical that aids in the conversion of NOx into harmless nitrogen and water.
Diesel Exhaust Fluid (DEF) is a fundamental component of the Selective Catalytic Reduction (SCR) process, which is employed by diesel engine manufacturers to comply with EPA 2010 rules. BlueDEF is a harmless solution made out of 67.5 percent purified water and 32.5 percent automotive-grade urea. BlueDEF isn’t a gasoline or a gasoline additive. Instead, when BlueDEF is injected into the exhaust stream and passed via a catalyst, it aids in the conversion of NOx to nitrogen gas and water vapor, both of which are safe and natural components of the air we breathe.
- BlueDEF’s Purity Guarantee ensures that the DEF you’re buying has been rigorously tested to meet or exceed OEM specifications.
- It complies with the ISO-22241-1 DEF specification and is a diesel exhaust fluid recognized by the American Petroleum Institute (API).