Guidance document for subfleet averaging and reporting for on-road motorcycles: chapter 5


5. Calculation of Subfleet Average Emission Values

5.1 What is a subfleet average emission value?

A subfleet average emission value is the calculated average emission of a company's subfleet of motorcycles of a given model year, based on the actual number of motorcycles of that model year that are certified to a family emission limit (FEL). For any given model year, a company may calculate average emission values for one or more of the subfleets specified in section 4.2.

5.2 How is a subfleet average HC+NOx emission value calculated?

As outlined in subsection 32.3(1) of the Regulations, the subfleet average emission value for HC+NOx, expressed in g/km, is calculated in accordance with the following equation:

Image of equation
[1]

where

A   represents the applicable family emission limit, expressed to the same number of decimal places as the emission standard it replaced;
B   represents the useful life of the engine family expressed in years or kilometres; and
C   represents the total number of motorcycles in the engine family.

5.3 How is a subfleet average fuel tank permeation emission value calculated?

As outlined in subsection 32.3(2) of the Regulations, the subfleet average emission value for fuel tank permeation, expressed in g/m2/day, is calculated in accordance with the following equation:

Image of equation
[2]

where

A   represents the applicable family emission limit, expressed to the same number of decimal places as the emission standard it replaced;
B   represents the useful life of the engine family expressed in units of years; and
C   represents the number of motorcycles in the engine family multiplied by the average internal surface area of the motorcycles' fuel tanks, where the average internal surface area is expressed in square meters (m2) to at least three decimal places.

5.4 Are there provisions respecting the procedures for rounding the calculated subfleet average emission values?

Yes. As specified in subsection 32.3(3) of the Regulations, the average HC+NOx emission value and average fuel tank permeation emission value must be rounded to one decimal place.

Furthermore, consistent with the definition of “rounded” in section 1 of the Regulations, all rounding must be performed in accordance with method ASTM-E29-93a of the American Society for Testing and Materials.

5.5 If a company divides its subfleet into two groups for the purpose of the subfleet averaging provisions of the Regulations as set out in subsection 32.2(3), are additional average emission value calculations required?

Yes. If a company effectively divides its subfleet into two groups (i.e., Group A and Group B) for the purpose of the subfleet averaging provisions of the Regulations, based on the subfleet average value of those motorcycles that do not meet all of the criteria for inclusion in Group A, the company is also required to calculate a separate average emission value for its motorcycles that are part of Group B. The calculation of an average emission value for that group B is conducted using the same formula as for the entire subfleet, but with the necessary modifications (i.e., variables apply to groups instead of subfleets). This is set out in subsection 32.7(4) of the Regulations.

5.6 If a company divides its subfleet of Class III motorcycles into two groups to meet the subfleet averaging provisions of the Regulations as set out in subsection 32.2(3), are there any consequences with respect to its emission credits?

Yes. A company that divides its subfleet into two groups as set out in paragraph 32.2(3)(b) in order to meet the subfleet averaging requirements will not generate any credits, even if the average emission value for its Group B motorcycles is below the applicable standard. This is set out in subsection 32.4(1) of the Regulations.

5.7 When are companies required to calculate subfleet average emission values?

As set out in section 32.3 of the Regulations, a company is required to calculate an average emission value for any given subfleet that includes one or more motorcycles that conform to a family emission limit that is greater than the applicable emission standards.

In addition, if a company divides its subfleet into two groups pursuant to paragraph 32.2(3)(b), it is also required to calculate a subfleet average emission value for those motorcycles that are part of Group B.

5.8 Can a company calculate an average HC+NOx emission value for its subfleet of Class III motorcycles even if all its motorcycles conform to a family emission limit that is lower than the applicable emission standards?

Yes. A company can elect to calculate an average HC+NOx emission value for its subfleet of Class III motorcycles even if all motorcycles conform to a family emission limit (FEL) that is lower than the applicable emission standards in order to obtain credits that would be used to offset an HC+NOx emission deficit incurred in respect of its subfleet of Class I and Class II motorcycles. The calculation and use of credits/deficits is further explained in Chapter 6 of this document.

5.9 Do the subfleet averaging provisions also apply to Class I and Class II motorcycles certified to the HC emission standard?

No. A company can not use emissions averaging as the basis for demonstrating compliance with the HC emission standard for Class I and Class II motorcycles.

A company may use emissions averaging as the basis for demonstrating compliance only for those Class I and Class II motorcycles that are certified to a family emission limit for HC+NOx (i.e., optional emission standard for HC+NOx).

5.10 Do the subfleet averaging provisions also apply to Class III motorcycles certified to alternative HC emission standards for the 2006 and 2007 model years under the provision for companies manufacturing or importing a “small volume” of motorcycles?

No. A company that manufactures or imports a “small volume” of motorcycles and that elects to certify its motorcycles to the alternative HC emission standards can not use emissions averaging as the basis for demonstrating compliance with the Regulations for Class III motorcycles.

A company may use emissions averaging as the basis for demonstrating compliance only for those Class III motorcycles that are certified to a family emission limit for HC+NOx (i.e., HC+NOx emission standards applicable to all companies or to companies that manufacture or import a “small volume” of motorcycles after the 2007 model year).

5.11 Can a company include all motorcycles in its calculation of the average fuel tank permeation emission value?

No. Companies are allowed to include, in the calculation of the average fuel tank permeation emission value, only motorcycles that are certified to FELs and are equipped with non-metal fuel tanks. All other motorcycles must individually meet the fuel tank permeation emission standard.

5.12 Since the subfleet averaging provisions of the Regulations came into effect on November 2, 2006, are only those motorcycles manufactured on or after that date eligible to be included in the calculation of subfleet average emission values?

No. A company may include all of its 2006 model year motorcycles, including those manufactured before November 2, 2006, in the subfleet average calculations for the 2006 model year, as provided under subsection 32.3(4) of the Regulations. Similarly, a company may also elect to include all of its 2007 model year or only those manufactured after November 2, 2006, in the subfleet average calculations for the 2007 model year.

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