Learn about Verified Technologies for Clean Diesel
- Retrofit technologies
- Repair, rebuild and repower
- Operational strategies for idling reduction
- Cleaner fuels
Diesel engines must comply with EPA emission standards to receive EPA certification. Retrofit technologies are products that may be added to further reduce emissions from certified engine configurations.
Engine exhaust after-treatment technologies are the most common retrofit technologies that:
- Are installed in the exhaust system to reduce emissions;
- May be part of the originally certified emission control system of vehicle; and
- Should not negatively impact engine or vehicle operation.
Examples: Diesel particulate filters (DPFs) and diesel oxidation catalysts (DOCs).
Retrofit technologies may also include:
- Crankcase emission control devices;
- Engine component upgrades; or
- Other modifications that reduce emissions.
Because they are designed and evaluated to reduce emissions from certified engine configurations, retrofit technologies should be added only to properly maintained engines.
- If your engine has a malfunctioning or damaged component, it should be repaired quickly to avoid additional damage to the engine, vehicle, and emission control system.
- Diesel engines often can be rebuilt with certain emission control components and continue to operate in the same capacity. An engine in need of rebuilding may have low power, increased emissions and increased fuel consumption. In some cases an engine can be rebuilt to comply with cleaner emission standards.
- Replacing an older engine with a new one which has been certified to cleaner emission standards is an option to repower some equipment and vehicles. Repowering with a new engine may extended the life of the machine, reduce fuel consumption, and significantly reduce emissions.
Operational strategies are ways of improving efficiency that may reduce engine run time and emissions. Operational strategies include: improving the flow of vehicles to reduce idle time or miles traveled while performing the same task.
Limiting engine idling can reduce emissions and fuel consumption. Idle reduction technologies are available for providing amenities such as cabin heat and air conditioning without operating the main engine.
Operational strategies may be unique for a given locality or business and may need periodic review to determine if additional changes are necessary to maintain or improve performance.
- Learn About Idling Reduction Technologies (IRTs) for Trucks
- Learn About Idling Reduction for Locomotives
Proper engine maintenance can optimize fuel economy and extend engine life while reducing harmful emissions. Retaining quality maintenance records are important for tracking and scheduling manufacturer-recommended maintenance.
Emissions may be reduced by using fuels with certain properties or by using alternative fuels. Ultra-low sulfur diesel (ULSD) fuel as well as biodiesel blends will reduce emissions. Engines certified to operate on alternative fuels such as liquid petroleum gas (LPG), compressed natural gas (CNG), and liquefied natural gas (LNG) can also reduce emissions.
- Clean Fuels: Alternative Fuel Options Related Links for State and Local Transportation Resources
- Vehicle and Engine Alternative Fuel Conversions
- Alternative Vehicle Fuels