From: Moulis, Charles

Sent: Thursday, January 23, 2014 5:49 PM

To: Jed R. Mandel, EMA; John Cabaniss, Global Automakers; Giedrius 

Ambrozaitis, Alliance of Automobile Manufacturers

Subject: Potential Revisions for DEF Replenishment Regulations

Attachments: Review Draft SCR Regs 012314.docx

As you know, EPA proposed last year to codify the DEF refill policy it has been applying to SCRequipped highway and nonroad engines through the (b)(7) process. That (b)(7) policy allowed 

manufacturers to specify DEF refill without meeting the minimum maintenance intervals that 

would otherwise apply for catalyst maintenance, provided they incorporated features 

(including performance inducements) to ensure that engines do not operate without DEF.

In response to comments, we are now considering shorter refill intervals than were proposed in 

the NPRM (and thus shorter than were allowed under the (b)(7) process). As part of our 

consideration of these shorter intervals, we are also considering other changes to the proposed 

regulatory text. In particular, we are considering the following clarifications:

1. Clarifying that intervals for chassis-certified vehicles may be calculated based on typical 

operation, while for engines they must be based on worst case operation.

2. Clarifying that certain demonstrations identified in §86.004-25(b)(6)(ii), §86.1834-

01(b)(6)(ii), and §1039.125(a)(1) are not sufficient to demonstrate that DEF 

replenishment will occur.

3. Clarifying that any size DEF tank may be used for laboratory engine testing.

While these specific provisions were not explicitly discussed in the NPRM, they reflect the 

broader principle that was discussed – that the rulemaking is generally codifying the existing 

approach to addressing DEF refills. Since these clarifications merely reflect what has applied 

under the (b)(7) process, we believe they represent a logical outgrowth of the NPRM.

Nevertheless, we believe it is appropriate to provide affected parties the opportunity to 

comment on the regulatory text we are considering, which is attached.

Since we share the manufacturers’ interest in completing this rule very soon, we are asking that 

you let us know by January 30th if you have comments on these possible clarifications, which 

are highlighted in the attached regulatory text. Please note that we are not asking for 

additional comments on the intervals themselves beyond what manufacturers already provided 

during the official comment period.

I look forward to hearing from you.
HEAVY-DUTY

§ 86.004-25 Maintenance.

* * * * *

(b) * * *

(4) For diesel-cycle heavy-duty engines, emission-related maintenance in addition to or at 

shorter intervals than the following specified values will not be accepted as technologically 

necessary, except as provided in paragraph (b)(7) of this section:

* * * * *

(v) For engines that use selective catalytic reduction, the diesel exhaust fluid (DEF) tank must be 

sized so that the replenishment of diesel exhaust fluid can occur at an interval, in miles or hours 

of vehicle operation, that is no less than the miles or hours of vehicle operation corresponding to 

the vehicle’s fuel capacity. Use good engineering judgment to ensure that you meet this 

requirement for worst case operation. For example, if your highest rate of DEF consumption 

(relative to fuel consumption) will occur under highway driving conditions, the DEF tank should 

be large enough that a single tank of DEF would be enough to continue proper operation of the 

SCR system for whatever number of highway miles is possible with a single tank of fuel. For 

laboratory engine testing, any size DEF tank and/or fuel tank may be used. For our testing of 

engines, we may require you to provide us with a production type DEF tank, including any 

associated sensors.

* * * * *

(6)(i) The following components are defined as critical emission-related components:

* * * * *

(H) Components comprising the selective catalytic reduction system (including diesel exhaust 

fluid tank).

(I) Any other component whose primary purpose is to reduce emissions or whose failure would 

commonly increase emissions of any regulated pollutant without significantly degrading engine 

performance. 

* * * * *

(ii) All critical emission-related scheduled maintenance must have a reasonable likelihood of 

being performed in-use. The manufacturer shall be required to show the reasonable likelihood of 

such maintenance being performed in-use, and such showing shall be made prior to the 

performance of the maintenance on the durability data vehicle. Critical emission-related 

scheduled maintenance items which satisfy one of the conditions defined in paragraphs (b)(6)(ii) 

(A)-(F) of this section will be accepted as having a reasonable likelihood of the maintenance 

item being performed in-use, except that for DEF replenishment, the manufacturer must satisfy 

paragraph (b)(6)(ii)(A) or (F) for us to accept that there is a reasonable likelihood of the 

maintenance item being performed in-use.

* * * * *
LIGHT-DUTY 

§ 86.1834-01 Allowable maintenance.

* * * * *

(b) * * *

(4) For diesel-cycle vehicles, emission-related maintenance in addition to, or at shorter intervals 

than the following will not be accepted as technologically necessary, except as provided in 

paragraph (b)(7) of this section:

* * * * *

(iii) For vehicles that use selective catalytic reduction, the replenishment of diesel exhaust fluid 

shall occur at an interval that is no less than 4,000 miles for typical operation. 

* * * * *

(6) * * *

(i) * * *

(H) Components comprising the selective catalytic reduction system (including diesel exhaust 

fluid tank).

(I) Any other component whose primary purpose is to reduce emissions or whose failure would 

commonly increase emissions of any regulated pollutant without significantly degrading engine 

performance.

* * * * *

(ii) All critical emission-related scheduled maintenance must have a reasonable likelihood of 

being performed in use. The manufacturer shall be required to show the reasonable likelihood of 

such maintenance being performed in use, and such showing shall be made prior to the 

performance of the maintenance on the durability data vehicle. Critical emission-related 

scheduled maintenance items which satisfy one of the conditions defined in paragraphs (b)(6)(ii) 

(A)-(F) of this section will be accepted as having a reasonable likelihood of the maintenance 

item being performed in-use, except that for DEF replenishment, the manufacturer must satisfy 

paragraph (b)(6)(ii)(A) or (F) of this section for us to accept that there is a reasonable likelihood 

of the maintenance item being performed in-use.
NONROAD

§ 1039.125 What maintenance instructions must I give to buyers?

* * * * *

(a) * * *

(1) You demonstrate that the maintenance is reasonably likely to be done at the recommended 

intervals on in-use engines. We will accept scheduled maintenance as reasonably likely to occur 

if you satisfy any of the following conditions, with the exception that paragraphs (a)(1)(ii) and 

(iii) of this section do not apply for DEF replenishment:

* * * * *

(2) * * *

(iii) For SCR systems, the minimum interval for replenishing the diesel exhaust fluid is the 

number of engine operating hours necessary to consume a full tank of fuel starting from full fuel 

capacity for the equipment. Use good engineering judgment to ensure that you meet this 

requirement for worst case operation. For laboratory engine testing, any size DEF tank and/or 

fuel tank may be used. For our testing of engines, we may require you to provide us with a 

production type DEF tank, including any associated sensors.

(3) * * *

(iii) For SCR systems, the minimum interval for replenishing the diesel exhaust fluid is the 

number of engine operating hours necessary to consume a full tank of fuel starting from full fuel 

capacity for the equipment. Use good engineering judgment to ensure that you meet this 

requirement for worst case operation. For laboratory engine testing, any size DEF tank and/or 

fuel tank may be used. For our testing of engines, we may require you to provide us with a 

production type DEF tank, including any associated sensors.

* * * * *