In the future effort to set marine Tier 3 emission levels, we will revisit the appropriate range of fuel properties for in-use testing in the context of the emission standards we set at that time.
4. Adjustable Parameters
Marine diesel engines are often designed with adjustable components to allow the engine to be adjusted for maximum efficiency when used in a particular application. This practice simplifies marine diesel engine production, since the same basic engine can be used in many applications. We recognize the need for this practice, but are also concerned about varying emission levels across the range of adjustment. We are therefore generally requiring that engines meet the emission standards when operated anywhere within the adjustable range (see 40 CFR 94.205). In most cases, this means engine manufacturers will be required to design their engines to prevent adjustments outside the specified range to ensure that engines are always operated within the specified range of adjustment. However, consistent with the approach used in the locomotive rule, we may allow manufacturers to specify in their applications for certification a narrower range of adjustment for these components across which the engine is certified to comply with the applicable emission standards, and demonstrate compliance across that range. For these engines, this allowance means that a manufacturer would specify a range of fuel injection timing, for example, over which the engine complies with the emission standards. This range could be designed to account for differences in fuel quality. Operators are then prohibited by the anti-tampering provisions from adjusting engines outside of this range.
BILLING CODE 6560-50-P
