This section describes durability demonstration procedures for exhaust emissions. Eligible small-volume manufacturers or small-volume test groups may optionally meet the requirements of §§ 86.1826 and 86.1838 instead of the requirements of paragraphs (a) through (m) of this section. A separate durability demonstration is required for each durability group.
te for a temperature bin = th e((R/Tr)-(R/Tv))
Total te = Sum of te over all the temperature bins
Bench-Aging Time = A (Total te)
Where:
A = 1.1 This value adjusts the catalyst aging time to account for deterioration from sources other than thermal aging of the catalyst.
R = Catalyst thermal reactivity coefficient. You may use a default value of 17,500 for the SBC.
th = The time (in hours) measured within the prescribed temperature bin of the vehicle's catalyst temperature histogram adjusted to a full useful life basis e.g., if the histogram represented 400 miles, and full useful life was 100,000 miles; all histogram time entries would be multiplied by 250 (100000/400).
Total te = The equivalent time (in hours) to age the catalyst at the temperature of Tr on the catalyst aging bench using the catalyst aging cycle to produce the same amount of deterioration experienced by the catalyst due to thermal deactivation over the vehicle's full useful life.
te for a bin = The equivalent time (in hours) to age the catalyst at the temperature of Tr on the catalyst aging bench using the catalyst aging cycle to produce the same amount of deterioration experienced by the catalyst due to thermal deactivation at the temperature bin of Tv over the vehicle's full useful life.
Tr = The effective reference temperature (in °K) of the catalyst on the catalyst bench run on the bench aging cycle. The effective temperature is the constant temperature that would result in the same amount of aging as the various temperatures experienced during the bench aging cycle.
Tv = The mid-point temperature (in °K) of the temperature bin of the vehicle on-road catalyst temperature histogram.
40 C.F.R. §§86.1823-08