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Maintenance Tips
As fleets move forward with clean diesel projects, some important technical points regarding fleet maintenance should be considered. The guidance below is based on lessons learned from existing EPA clean diesel projects.
Maintenance Practices
Good maintenance practices are necessary to achieve low emissions and optimal fuel economy. Recommended actions for maintenance practices include:
- Replacing intake air filters and monitoring fuel and oil consumption.
- Engines with high fuel or oil consumption may need repair and should not be retrofitted until proper operation is confirmed.
- Repairing all exhaust leaks.
- Exercising caution when considering the use of fuel additives.
- An example of such would be to correct a confirmed lubricity problem or to avoid gelling in winter. Fuel additives may impact engine and emission control system durability. All fuel additives used in on-road vehicles must be registered with EPA. Information on EPA's fuel registration process and a list of registered fuel additives can be found at http://www.epa.gov/otaq/additive.htm. Registration does not imply endorsement of product safety but provides information about the content of the additive. As discussed in item 3 of Fuels Practices below, all diesel fuel sold in the U.S. since January 2005 must meet a fuel lubricity specification established by the American Society for Testing and Materials (ASTM). It is not necessary for end-users to add fuel lubricity additives to highway diesel fuel.
- Retaining engine profile information.
- If fleet vehicles are evaluated for retrofit technology options (such as exhaust temperature data logging required for diesel particulate filters), obtain and keep documentation of the evaluation and the results, such as copies of the exhaust temperature profile and data logging records.
- Monitoring engines and fuel systems for leaks.
- Prior to installing equipment or changing fuels, visually inspect the engine and fuel system to confirm system integrity. Correct fuel and or oil leaks prior to installing aftertreatment technologies. If switching to ultra low sulfur diesel (ULSD) fuel or other fuels, periodically inspect the engine, fuel pump and fuel lines, and contact your engine manufacturer representative(s) to determine if any technical service bulletins are applicable to your engines.
Retrofit Technology Considerations
Some retrofit systems such as crankcase emission control systems and diesel particulate filters (DPFs) may require periodic maintenance. Be sure to document and monitor this maintenance. Work with your technology supplier to have an adequate supply of replacement items such as disposable crankcase and fuel filters. Remember that:
- Changes in maintenance needs may indicate other problems.
- For example, DPFs may mask problems with fuel injectors that might otherwise be recognized by increased levels of exhaust opacity (smoke). Consequently on a filter-equipped engine, an injector problem might be identified by an increase in fuel consumption. Similarly, increased oil burning from bad valve seals or a turbocharger problem may result in the need for more frequent diesel particulate filter cleaning.
- Onboard oil burning systems should not be used with most aftertreatment technologies.
- If aftertreatment devices (such as catalysts or DPFs) are installed, do not burn (bulk blend) crankcase oil in your vehicles and do not use onboard oil burning systems. These systems should be removed or disconnected (not just turned off) prior to installing aftertreatment technologies.
Fuels Practices
When switching to a different fuel, it is recommended that you:
- Obtain the fuel analysis.
- Obtaining a copy of the fuel analysis (before and after the switch, whether it is ULSD or biodiesel) aids in monitoring any changes. The fuel analysis should include at the least results and specifications for: sulfur, cetane, aromatics, lubricity, distillation, and flash point.
- Monitor and replace fuel filters as necessary.
- When switching to ULSD some fleets have changed fuel filters after 2 or 3 tanks of fuel as they have been concerned with this cleaner fuel acting as a solvent to remove sediment from fuel tanks. EPA has not been able to document this as a common occurrence, nor do we know if the issues seen are actually related to the use of ULSD. Nevertheless, it may be a practice to consider.
- Remember that extra highway diesel fuel lubricity additives are unnecessary.
- Beginning in January of 2005, all highway diesel fuel sold in the U.S. must meet a new ASTM fuel lubricity standard (ASTM D 975). Any fuel lubricity additives necessary to meet this new specification will be added by the fuel suppliers. End-users do not need to add fuel lubricity additives.
- Watch for fuel leaks.
- Checking with your fuel supplier and engine manufacturer for more information on recommended best maintenance practices is a prudent step to ensure your fleet's success when transitioning to ULSD.
- Talk to your fuel supplier.
- Checking with your fuel supplier and engine manufacturer for more information on recommended best maintenance practices is a prudent step to ensure your fleet's success when transitioning to ULSD.
- Visit www.clean-diesel.org
for information on the introduction of ultra-low sulfur diesel.
- EPA is a member of a recently formed industry-government organization named the Clean Diesel Fuel Alliance (CDFA). CDFA's web site contains information regarding the introduction of ULSD, including common questions and answers regarding fuel lubricity and potential maintenance issues.