The requirement for meeting Tier 4 Final emission standards set by the Environmental Protection Agency (EPA) has been a phased implementation over the past decade. The final stage was fully implemented in December 2017 and now includes all off-road, diesel-engine machines ranging from 25 horsepower and above. In other words, if you are in the market to buy a new diesel-engine air compressor fresh off the factory line, it will be a Tier 4 Final model.

Previously, some manufacturers were allowed flex credits that allowed them to continue to manufacture machines at a lower tier level, such as Tier 3 and Tier 4 Interim. Now, all new equipment on the market is Tier 4 Final, regardless of manufacturer.

While the complex technology needed to meet EPA emissions standards has increased the development and retail cost of machines, most manufacturers have added advancements that will improve field operation, productivity and profitability. These advancements — improved efficiency, fuel cost savings, less maintenance — should be considered when deciding between used or new air compressor models for your fleet.

Tier 4 Final air compressors are not the same machines simply repackaged with new engines. Additional technology and features have been incorporated to deliver better efficiency, more uptime and extra value on the jobsite.

What’s Different About Tier 4 Final Air Compressors?

So, what’s so different about Tier 4 Final air compressors? To meet EPA emissions regulations, Tier 4 Final engines have been designed with an aftertreatment system, specifically selective catalytic reduction (SCR) technology that reduces particulate matter and destroys nitrogen oxide (NOx) gases contained in engine exhaust.

The SCR technology requires the use of diesel exhaust fluid (DEF) to aid the system in destroying harmful emissions. DEF is stored in an onboard tank that must be refilled at regular intervals, similar to refilling a fuel tank. The Tier 4 Final machines have a gauge on the control panel that monitors DEF level in the same manner as fuel levels.

Most DEF tanks follow a 2-to-1 interval, meaning the onboard DEF tank is refilled once for every two diesel fuel refills. The two fill points are typically placed side by side so both can be refilled at the same time. To prevent refill mix-ups, the neck of the DEF tank is smaller in diameter than the diesel opening. All DEF filler caps are blue, while diesel caps are green.

The cost of DEF is typically around $2 to $3 per gallon, and DEF tanks generally range in size from 3 gallons to 17 gallons.

How to Handle DEF

DEF is a colorless, non-hazardous chemical and is susceptible to variations in hot and cold temperatures. The shelf life of DEF can be extended by storing it out of direct sunlight, in an airtight container and between 12 and 86 degrees Fahrenheit (-10 to 30 degrees Celsius).

It’s also important to limit the potential for contaminants such as dirt and dust to enter the DEF supply. Contamination can damage the catalyst in an SCR system. To reduce the risk of contamination, fill the DEF tank directly from the DEF container. The use of funnels or intermediate containers should be restricted to only DEF and not used with other fluids. Purity and concentration are critical with DEF, so be sure to work with a local dealer to better understand how to store and handle DEF fluid.

The Importance of Fuel Quality

As Tier 4 Final diesel engines have become increasingly refined to meet emissions regulations, they also have become less tolerant of contamination. Fine particles of dust, dirt or rust, and even trace amounts of water or mildew, in diesel fuel can affect the performance of the engine and, in turn, the air compressor.

Using genuine OEM fuel filters can help protect sensitive engine components from contaminants by trapping particulates down to 2 microns, but the first line of defense is a clean fuel source.

Testing fuel supply tanks for contaminants every six months and ensuring that fuel entering a storage tank passes through a dispensing filter go a long way toward preventing contaminants from entering the machine. Additionally, fuel tank filters should be capped and the tank vent must be filtered. Tank filters typically have a 10-micron-or-fewer fuel filter to help remove moisture as fuel is dispensed through the vent.

Benefits of Tier 4 Final Air Compressors

It’s true that Tier 4 Final air compressors are more complex machines than earlier models. They require additional service with DEF and they cost more upfront. But they also contain a number of enhancements and additional functionality that can benefit a drilling operation — immediately and long term. Those benefits include higher fuel efficiency, better diagnostics and maintenance schedules similar to their predecessors.

Fuel efficiency: Tier 4 Final engines burn fuel in a more efficient manner than previous models. The newer technology required to meet EPA emission regulations allows the engine to utilize a fine mist of fuel instead of a full line of liquid fuel as previous-tier engines did. The ability to more effectively burn every ounce of diesel fuel translates into significant fuel cost savings over time.

The technology also results in better cold weather performance, particularly the ability to start the engine in below zero temperatures.

Enhanced diagnostics for increased uptime: Newer control systems on Tier 4 Final air compressors allow for improved diagnostics and greater insight into how the air compressor operates over time. For example, Doosan Portable Power Tier 4 Final air compressors keep a history of up to 60 alarm codes compared to 15 codes of previous-tier models. The extended code history allows a service technician to diagnose issues and troubleshoot for preventive maintenance.

For instance, a warning code that the inlet vacuum is too high can be resolved by changing the air filter at the drilling site instead of bringing the machine into the shop. The end result is keeping the machine operating on-site for maximum productivity.

Maintenance: Overall maintenance schedules have not changed in the transition to Tier 4; however, recommended oils have changed to CJ-4 engine oils. If equipment operators fill an air compressor with incorrect engine oil, it can cause costly damage to the machine’s internal components. These components can become plugged, corroded and, ultimately, not work efficiently. Now more than ever, making the right choice is critical to engine performance and longevity. Always check oil preferences with a compressor’s original manufacturer to ensure best performance.

High Quality, High Tech, High Value

Tier 4 Final air compressors are every bit as high quality, every bit as reliable and every bit as good an investment as in previous years. By understanding the required maintenance, how to properly store and handle DEF, and the additional technology and enhancements, equipment owners and operators can be better educated about the benefits and value a Tier 4 Final air compressor can bring to the operation.