National Clean Diesel Campaign (NCDC)
Proper engine maintenance is necessary for best engine performance, optimum fuel economy, extended engine life and to control emissions. Overall operating costs can also be reduced with regular vehicle and engine maintenance. Good maintenance records are important for tracking and scheduling manufacturer-recommended maintenance for warranty and retrofit purposes. All new engines have been certified to comply with EPA emission standards, and when properly maintained and operated, a diesel engine should have a long useful life.
Common issues that can be resolved with proper maintenance include:
- Maladjusted fuel racks
- Clogged, worn or mismatched fuel injectors
- Improperly adjusted valve lash or governors
- Leaking turbocharger seals and dirty aftercoolers
- Improperly operating intake air sensors
- Irregular closed crankcase filter replacement
- Defective or maladjusted smoke puff limiters
- Dirty or restricted air filters
- Dirty or restricted fuel filters
- Over fueling
- Poor fuel quality
- Irregular Oil Changes
- Poor Oil Quality
- Faulty fuel injection pumps
- Improper injection timing
A properly maintained engine is necessary for retrofit technologies to effectively reduce emissions, maintain durability, and have reduced maintenance requirements. Tracking fuel and oil consumption is important before and after retrofit technologies are installed. Sudden changes in fuel or oil consumption can be an indication of needed engine repair, and an exhaust after-treatment device like a DPF may eliminate the smoke that would otherwise be visible from an engine malfunction. Exhaust after-treatment devices may be damaged or need cleaning in such cases. Consult the device manufacturer’s recommended maintenance practices if an engine malfunction occurs.
Crankcase oil must not be burned in modern diesel engines or engines with after-treatment technologies. Crankcase oils may contain debris that can clog fuel filters or fuel injectors or additives that can damage after-treatment devices.
An engine in need of repair may have reduced power, increased emissions and increased fuel consumption. Repairs may be necessary for many reasons including broken, worn or malfunctioning components. These problems can lead to greater engine or emission control system damage. An engine in need of repair is not appropriate for retrofit, and an engine that needs frequent repairs should be carefully evaluated before installing retrofit technologies.
As described above, tracking fuel and oil consumption is important and sudden changes in fuel or oil consumption can be an indication of needed engine repair. For example, a leaking turbocharger oil seal can quickly lead to other engine or emission control system issues. Exhaust after-treatment devices like DPFs may eliminate the smoke that would otherwise be visible from an engine with a leaking oil seal or bad fuel injector. In such cases, exhaust after-treatment devices may be damaged or in need of cleaning. Consult the device manufacturer’s recommended maintenance practices if an engine malfunction occurs. Repair and maintenance records should be retained and reviewed periodically to insure that other unforeseen problems do not go unresolved.
Diesel engines often can be rebuilt and continue to operate in the same capacity. An engine in need of rebuild may have low power, increased emissions and increased fuel consumption. Engine manufacturers often can supply rebuild kits as well as fully rebuilt engines.
Engines can sometimes be rebuilt to comply with cleaner emission standards. An engine upgrade kit may contain replacement components that will improve the overall emission performance of the engine and in some cases, may also improve fuel economy.
A recently rebuilt engine in proper operating condition is a good candidate for retrofit with an appropriately verified technology. An engine with low compression or high crankcase flow-by flow rate is not a good candidate for retrofit.
Engine replacement (repower) may be a cost-effective emissions reduction strategy when a vehicle or machine has a long useful life and the cost of the engine does not approach the cost of the entire vehicle or machine. Examples of good potential replacement candidates include marine vessels, locomotives, and large construction machines.
Older diesel vehicles or machines can be repowered with newer diesel engines or in some cases with engines that operate on alternative fuels (e.g. CNG, LNG, electric). The original engine is taken out of service and a new engine with reduced emission characteristics is installed. Significant emission reductions can be achieved, depending on the newer engine and the vehicle or machine’s ability to accept a more modern engine and emission control system.
Replacement can include substituting a cleaner highway engine for a nonroad engine. Replacements often require some re-engineering work due to differences in size and configuration. Typically there are benefits in fuel efficiency, reliability, warranty, and maintenance costs.
- EPA Certified Engines
- Guide to Available Natural Gas Vehicles and Engines (PDF) (7 pp, 85K, About PDF)
- Northeast Diesel Collaborative’s Marine Repower Guide
- Midwest Clean Diesel Marine & Locomotive Repowers Webinar