What Cummins Emission Solutions Does

Cummins Emission Solutions is a division of Cummins Inc. that designs and manufactures equipment to reduce harmful pollutants from diesel engines. The company makes aftertreatment systems — devices that clean exhaust gases after they leave the engine but before they exit the tailpipe. These systems help engines meet federal and state emission standards set by the Environmental Protection Agency (EPA) and California Air Resources Board (CARB).

The systems work by converting nitrogen oxides (NOx), particulate matter, and other pollutants into less harmful substances. Different Cummins systems handle different pollutants and work with different engine sizes, from light-duty pickup trucks to heavy-duty commercial trucks and industrial equipment. The company also makes systems for off-road engines used in construction, mining, and agriculture.

Cummins Emission Solutions operates manufacturing plants across the United States and internationally. The division serves original equipment manufacturers (OEMs) — the companies that build trucks and engines — as well as retrofit markets where older equipment receives new emission control systems to meet updated standards.

Key Takeaways

  • Cummins Emission Solutions makes aftertreatment devices that reduce pollutants from diesel engines to meet EPA and state emission standards.
  • The systems convert nitrogen oxides and particulate matter into less harmful substances through chemical and mechanical processes.
  • These systems are installed on new engines at the factory or retrofitted onto existing equipment to bring it into compliance with emission rules.
  • Different system types serve different engine sizes and applications, from pickup trucks to heavy industrial equipment.
  • The technology is required by law in most states and is a major cost factor in new vehicle and equipment pricing.

How Selective Catalytic Reduction (SCR) Systems Work

One of the most common Cummins Emission Solutions products is a Selective Catalytic Reduction (SCR) system. SCR systems reduce nitrogen oxides, which are a major contributor to smog and respiratory problems. The system works by injecting a liquid called diesel exhaust fluid (DEF) into the hot exhaust stream. DEF is a mixture of urea and deionized water.

When DEF mixes with hot exhaust gases inside a catalyst chamber, a chemical reaction occurs that converts NOx into nitrogen gas and water vapor — both harmless substances already in the air. The catalyst is typically made of zeolite or other materials that speed up this chemical reaction. The system requires a separate tank to hold DEF, a pump to inject it at the right rate, and sensors to monitor the process.

SCR systems are now standard on most new diesel trucks and engines sold in the United States. They are more efficient than older emission control methods and allow engines to run at higher temperatures, which improves fuel economy. However, they require regular DEF refills — a typical heavy-duty truck may need to refill every 5,000 to 10,000 miles depending on engine size and driving conditions.

Diesel Particulate Filters and Regeneration

Cummins Emission Solutions also manufactures diesel particulate filters (DPF), which trap soot and ash particles in the exhaust before they leave the engine. The filter is a ceramic or metal structure with tiny channels that allow gases to pass through while catching solid particles. Over time, the filter fills with soot and must be cleaned — a process called regeneration.

Regeneration happens automatically during normal driving when the engine reaches high enough temperatures. The system burns off the trapped soot, turning it into ash that remains in the filter. In some cases, if the filter becomes too full during low-speed or city driving, the engine computer triggers active regeneration, which heats the exhaust to burn the soot intentionally. This process uses extra fuel and takes several minutes.

If a DPF becomes severely clogged and regeneration cannot clear it, the engine may enter a reduced-power mode to prevent damage. At that point, the filter must be professionally cleaned or replaced. Cummins DPF systems are designed to last the life of the vehicle under normal conditions, though maintenance and driving habits affect actual lifespan.

Why Emission Standards Require These Systems

The EPA and CARB set emission standards to protect public health and air quality. Diesel engines produce nitrogen oxides and particulate matter that contribute to smog, acid rain, and respiratory diseases. Standards have become progressively stricter over the past two decades, requiring manufacturers to reduce emissions by 90 percent or more compared to engines from the 1990s.

Federal standards explore nationwide, but California and several other states have adopted stricter limits under a waiver from the EPA. This means trucks and equipment sold in California or the Northeast must meet higher standards than those sold in other states. Cummins manufactures different system configurations to meet these varying regional requirements.

Manufacturers like Cummins invest heavily in emission control technology because they are legally required to meet these standards. The cost of aftertreatment systems is built into the price of new vehicles and equipment. Without these systems, new diesel engines could not be legally sold in most of the United States.

Aftertreatment Systems for Different Engine Types

Cummins Emission Solutions makes systems for several categories of engines. Heavy-duty on-road engines — used in Class 8 trucks and buses — typically use SCR systems combined with DPF technology. Medium-duty engines in delivery trucks and smaller commercial vehicles may use similar systems or alternative configurations depending on the manufacturer's design.

Light-duty diesel engines in pickup trucks use smaller, integrated systems that take up less space. Off-road engines used in construction equipment, agricultural machinery, and industrial applications have their own emission standards and system designs. Cummins also manufactures systems for stationary engines used in power generation and industrial processes.

Each system type is engineered for the specific duty cycle and operating conditions of its process. A highway truck engine runs at steady high temperatures, while a construction excavator operates in stop-and-start cycles with frequent idle periods. The aftertreatment system must perform reliably in these different environments.

Maintenance and Fluid Requirements

Owners of engines with Cummins Emission Solutions systems must maintain them properly to keep them working. The most visible maintenance requirement is diesel exhaust fluid (DEF) refills. DEF is sold at truck stops, fuel stations, and online retailers. It is inexpensive — typically a few dollars per gallon — but must be purchased regularly.

DEF must meet strict purity standards set by the American Petroleum Institute (API). Using contaminated or incorrect fluid can damage the SCR system and trigger warning lights. Most modern trucks have warning systems that alert the driver when DEF is running low, and some engines will limit power if DEF runs out completely.

Diesel particulate filters require less active maintenance but benefit from regular oil changes and proper engine maintenance. Using high-quality diesel fuel and keeping the engine tuned helps the DPF regenerate properly. Some owners in severe-duty applications may need professional DPF cleaning more frequently than others.

Cost Impact on Vehicle and Equipment Pricing

Aftertreatment systems add significant cost to new vehicles and equipment. For a heavy-duty truck, the SCR and DPF systems can add several thousand dollars to the purchase price. This cost is passed to buyers and is one reason new diesel trucks are more expensive than older models.

Over the life of the vehicle, owners also pay for DEF fluid, which adds to operating costs. A fleet operator running multiple trucks may spend thousands of dollars annually on DEF. However, the improved fuel economy from modern emission control systems often offsets some of this cost, and the systems are designed to last the vehicle's useful life without major repairs.

Used equipment and vehicles with older emission systems may be worth less because they cannot be sold in states with stricter standards. This creates a market advantage for newer equipment that meets current emission rules across multiple states.

Frequently Asked Questions

What is diesel exhaust fluid and where do I buy it?

Diesel exhaust fluid (DEF) is a mixture of urea and deionized water used in SCR systems to reduce nitrogen oxides. It is sold at truck stops, fuel stations, Walmart, Amazon, and specialty retailers. A gallon typically costs between two and five dollars. Most trucks hold 10 to 20 gallons and need refills every 5,000 to 10,000 miles.

Can I use my diesel truck if the DEF tank is empty?

Modern trucks will not allow the engine to start or will limit power severely if DEF is completely empty. Some systems give several hundred miles of warning before shutting down. You must refill DEF before the tank reaches zero to avoid being stranded. Older trucks without DEF systems do not have this limitation.

How often does a diesel particulate filter need to be cleaned?

Under normal driving conditions, a DPF regenerates automatically and does not require manual cleaning. However, trucks used in severe-duty applications — such as constant idling or low-speed operation — may need professional cleaning every 100,000 to 200,000 miles. Highway trucks typically go much longer without needing service.

Do emission control systems reduce fuel economy?

Modern SCR and DPF systems actually improve fuel economy compared to older emission control methods. The systems allow engines to run more efficiently. However, active DPF regeneration uses extra fuel during the regeneration cycle, and DEF consumption adds a small ongoing cost to operation.

Can I remove or disable emission control systems?

Removing or disabling emission control systems is illegal under federal law and state laws in most jurisdictions. Violations can result in fines of thousands of dollars per vehicle and criminal penalties. Tampering also voids the vehicle warranty and can cause engine damage. Enforcement has increased significantly in recent years.