Mexico: Heavy-duty: Emissions

Overview

Mexico published NOM-044-SEMARNAT-2017, an update to heavy-duty emissions standards, on February 19, 2018. The regulation allows for compliance with A standards, allowing either U.S. 2004 or Euro IV equivalent standards, until June 30, 2019. The regulation introduced new AA and B standards on January 1, 2019. The option for compliance with AA standards, allowing equivalence with either Euro V or U.S. 2007, ends on December 31, 2020. The B standard, allowing equivalence with either Euro VI or U.S. 2010, remains in place indefinitely.  

Standard type
Conventional pollutant emission limits

Current Standard
NOM-044-SEMARNAT-2017 for diesel engines and NOM-076-SEMARNAT-2012 for engines that run on gasoline, liquified petroleum gas (LPG), and natural gas

Applicability
New on-road vehicles and engines for units above 3,857 kg of gross vehicle weight

History

The standard NOM-044-SEMARNAT-2006, adopted in 2006 as an update to NOM-044-SEMARNAT-1993, established emission limits for total hydrocarbons, non-methane hydrocarbons, carbon monoxide, nitrogen oxides, particles, and opacity for new heavy-duty diesel engines. The standard allowed compliance with either US 2004 or Euro IV equivalent standards from in July 2008 through June 2011. An Acuerdo (agreement) from SEMARNAT extended the regulatory timeline for compliance to June 2014, with a second acuerdo adopted in June 2014 extending the timeline indefinitely. A proposed modification to the standard was adopted in December 2014, requiring compliance with US 2010 or Euro VI equivalent standards starting January 1, 2018. The final revision, NOM-044-SEMARNAT-2017, was adopted in February 2018.

NOM-076-SEMARNAT-2012, was adopted on 27 November 2012 and establishes emissions for hydrocarbons, nitrogen oxides and carbon monoxide and evaporative emission limits for hydrocarbons for new heavy-duty engines that use gasoline, liquid petroleum gas (LPG), natural gas or other alternative fuels.

 

Technical Standards

Both NOM-044-SEMARNAT-2006 (diesel) and NOM-076-SEMARNAT-2012 (gasoline) are applicable to new engines intended for use in vehicles with a gross vehicle weight greater than 3,857 kg (8,500 lbs.) or for new vehicles of this size.

Diesel Engine Standards

2018 to present

The revised standard, NOM-044-SEMARNAT-2017 sets A, AA, and B standards for heavy-duty engines and complete heavy-duty vehicles with a gross vehicle weight above 3,857 kg. The following table shows the timing and equivalent standards under U.S. or European regulations.

Timing and alignment of NOM-044-SEMARNAT-2017
  Heavy-duty engines Complete vehicles
Implementation NOM-044 Aligned standard NOM-044 Aligned standard
Until June 30, 2019 1A U.S. 2004 3A California LEV I
2A Euro IV 4A Euro 4
January 1, 2019—December 31, 2020 1 AA U.S. 2007
2 AA Euro V 4AA Euro 5
From January 1, 2019 1 B U.S. 2010 3B U.S. 2010
2 B Euro VI 4B Euro 6
Limit values

Limit values for heavy-duty engines are shown in the following tables. Limits are set in grams per brake horsepower-hour (g/bhp-hr) for U.S.-aligned standards and in grams per kilowatt-hour (g/kWh) for Euro standards. Particle number and ammonia (NH3) limits are set as part of the Euro VI standards but have not been defined as limit values under EPA standards.

Emissions limits for heavy-duty engines
Aligned standard Standard Test Cycle CO NOx NMHC NMHC + NOx PM Particle number NH3
g/bhp-hr
U.S. 2004 1A SET & FTP 15.5 2.4 0.10
0.5 2.5
U.S. 2007 1AA SET & FTP 15.5 1.2 0.14 0.01
U.S. 2010 1B SET & FTP 15.5 0.20 0.14 0.01
Aligned standard Standard Test Cycle CO NOx NMHC HC PM Particle number NH3
g/kWh
Euro IV 2A ESC 1.5 3.5 0.46 0.02
ETC 4.0 3.5 0.55 0.03
Euro V 2AA ESC 1.5 2.0 0.46 0.02
ETC 4.0 2.0 0.55 0.03
Euro VI 2B WHSC 1.5 0.4 0.13 0.01 8.0 x 1011 10
WHTC 4.0 0.46 0.16 0.01 6.0 x 1011 10

The useful life requirements for heavy-duty engine standards are as follows. Useful life is defined as the reference values used in durability tests as part of new engine or vehicle certification for design and testing of emission control systems. Useful life does not refer to, nor is it equivalent to, the manufacturer warranty or in-use vehicle emissions.

Useful life requirements for heavy-duty engines
Aligned standard Standard Gross vehicle weight (kg) Useful life
Distance (km) Time (years)
U.S. 2004, U.S. 2007, and U.S. 2010 1A, 1AA, and 1B 3,857 – 8,845 177,023 10
8,846 – 14,970 297,721
14,971 and greater 700,046
Euro IV and

Euro V

2A and 2AA 3,857 – 15,999 200,000 6
16,000 and greater 500,000 7
Euro VI 2B 3,857 – 15,999 300,000 6
16,000 and greater 700,000 7

The standard includes optional alternative certification limits for medium-duty complete vehicles.

Emissions limits and useful life requirements for complete vehicles
Aligned standard Standard Gross vehicle weight (kg) Test cycle CO NOx NMHC PM Particle Number (#/km) Useful Life
g/km   km years
California LEV I 3A 3,857 – 4,539 FTP 75 0.311 0.121 0.037 193,121 11
4,540 – 6,350 0.435 0.143 0.037
U.S. 2010 3B 3,857 – 4,539 FTP 75 0.124 0.121 0.012 193,121 11
4,540 – 6,350 0.249 0.143 0.012
Aligned standard Standard Reference weight (kg) Test cycle CO NOx HC+NOx PM Particle Number (#/km) Useful Life
g/km km years
Euro 4 4A ≤2,840 NEDC 0.74 0.39 0.46 0.06 160,000 5
Euro 5 4AA ≤2,840 NEDC 0.74 0.28 0.35 0.005 160,000 5
Euro 6 4B ≤2,840 NEDC 0.74 0.125 0.215 0.005 6.0x1011 160,000 5

These limits can be used for medium-duty vehicles that are certified as complete vehicles, with testing done on a chassis dynamometer, rather than certified as an engine, with testing on an engine dynamometer. The 3B and 4B pathways for certification of complete vehicles were included in the original proposal, while 3A, 4A, and 4AA were added in the final standard.

On-Board Diagnostics and Compliance Inducements

The final standards require full OBD systems to be installed and operating on new vehicles meeting B standards. The type of OBD system must be listed in the certification documentation. Appendix A includes general OBD system requirements and a detailed description of the requirements—including monitoring thresholds and the systems and metrics to monitor—for OBD systems meeting the Euro VI and U.S. 2010 standards. As both U.S. and Euro standards require the full phase-in of OBD systems implementation of B standards, certification documentation under U.S. and Euro standards is used as the primary proof of compliance with OBD requirements.

The regulation requires that all vehicles meeting AA and B standards that are equipped with SCR systems (which require use of DEF for proper control of NOx) are equipped with the full suite of operating systems of alerts and driver inducements to ensure the correct functioning of these systems. These fail-safes include lights, auditory alarms, and requirements to safely limit vehicle operation in all cases of improper use, including lack of DEF, poor-quality DEF, and insufficient consumption or dosing of DEF. Both European and U.S. systems described in Appendix B also include anti-tampering mechanisms to ensure that users do not evade these requirements.

1993-2018

Emission standards for new heavy-duty diesel engines first became effective in model year 1993 and were based on US 1991 and later requirements, including the US Environmental Protection Agency (EPA) FTP transient test cycle. Standards for MY 1993-1998 were equivalent to US standards and compliance could be demonstrated through certification by US EPA. Under NOM-044, engines in Mexico are provided compliance options and can meet European standards, as measured on the official European test cycles (ETC and ESC), as an alternative to the EPA-based standards; compliance with standards can be demonstrated through:

  • Letter or proof issued by motor manufacturer, including earnings report issued by the testing laboratory,
  • Certificate or proof issued by the Environmental Protection Authority of the country of origin or country of certification, or
  • Certificate issued by Certification Bodies for the country of origin or country of certification.

In 2006, the standard NOM-044-SEMARNAT-2006 was adopted, establishing emission limits for total hydrocarbons, non-methane hydrocarbons, carbon monoxide, nitrogen oxides, particles, and opacity for new heavy-duty diesel engines. The standard allowed compliance with either US 2004 or Euro IV equivalent standards. The emission standards compliance timeline and equivalent limit values of the 1993 and 2006 standards are outlined below:

Max. Permissible Emissions Standards
Heavy-duty Vehicles
Compliance
Year Compliance Equivalent
1993 US EPA 1991
1994 US EPA 1994
1998 US EPA 1998
2006-2008 US EPA 1998 or Euro III
2008 US EPA 2004 or Euro IV
Notes: extended indefinitely.
Maximum Permissible Emissions for Heavy-duty Vehicles
limit values expressed as grams per brake horsepower-hour (g/bhp-hr)
Standard HC NMHC+NOx CO NOx Smoke
opacity %
(acceleration)
Smoke opacity %
(pull)
Smoke opacity %
(peak)
A1 1.3 N/A 15.5 4.0 20 15 50
B2 N/A 2.43 15.5 N/A 20 15 50
Notes:

1. Standard A Maximum permissible limits for engines and/or new units produced from 2006 until June 2008, obtained using the FTP (Federal Test Procedure) heavy-duty transient cycle.
2. Standard B Maximum permissible limits for engines and/or new units produced from July 2008 until July 2014, obtained using the SET (Supplemental Emissions Test).
3. Limit value could be 2.5 provided the NMHC are less than 0.5
Maximum Permissible Emissions for Heavy-duty Vehicles
limit values expressed as grams per kilowatt hour (g/kwhr)
Standard Test Method HC NMHC CO NOx Part Smoke Opacity3
A1 ESC 0.66 N/A 2.1 5.0 0.10 N/A
ETC N/A 0.78 5.45 5.0 0.16 N/A
B2 ESC 0.46 N/A 1.5 3.5 0.02 N/A
ETC N/A 0.55 4.0 3.5 0.03 N/A
Notes:

1. Standard A Maximum permissible limits for engines and/or new units produced from 2006 until June 2008, obtained using the ESC (European Stationary Cycle) and ETC (European Transient Cycle).
2. Standard B Maximum permissible limits for engines and/or new units produced from July 2008 until July 2014, obtained using the ESC (European Stationary Cycle) and ETC (European Transient Cycle).
3. The European Load Response (ELR) engine test has no applicable limit values in the above table except under Smoke Opacity, where values are 0.8 and 0.5 for standards A and B, respectively.

 

Gasoline, LPG, and NG Engine Standards

Emission standards for new heavy-duty engines fueled by gasoline, LPG, natural gas and other alternative fuels are specified by the NOM-076 standard, adopted in 1995, with later amendments in 2012. Similar to the diesel regulations, the emission standards are applicable to gas engines used in vehicles of GVW > 3,857 kg (8,500 lbs).

Gasoline and gaseous fueled engines are tested over the FTP transient test and must meet the US EPA-based emission standards shown in the following 2 tables.

Maximum Permissible Emissions for Heavy-duty Vehicles
Standard GVW HC
(g/bhp-hr)
NMHC
(g/bhp-hr)
CO
(g/bhp-hr)
NOx
(g/bhp-hr)
HCev3
g/test
A1 3,857kg ≤ GVW ≤ 6,350kg 1.1 N/A 14.4 4.0 3.0
> 6,350kg 1.9 N/A 37.1 4.0 3.0
B2 3,857kg ≤ GVW ≤ 6,350kg N/A 0.14 14.4 0.2 1.75
> 6,350kg N/A 0.14 14.4 0.2 2.3
Notes:

  1. Standard A refers to the maximum allowable limits for new units from the input into force until Standard B enters into force.
  2. Standard B provides the maximum allowable limits for new units produced, provided that there is full availability nationwide Magna gasoline or replacing it with content average of 30 ppm and 80 ppm maximum sulfur. These limits are tested using the test method Transient cycle. The implementation of this standard shall be 18 months after publication in the Official Journal of the Federation of the notice of full availability throughout the country.
  3. HCev measurement applies only to gasoline vehicles and LPG

Natural gas engines can alternatively be tested over the European Transition Cycle; relevant standards are show in the following table.

Maximum permissible emission for engines using natural gas as fuel
Standard CH4
(g/bhp-hr)
NMHC
(g/bhp-hr)
CO
(g/bhp-hr)
NOx
(g/bhp-hr)
Part
g/kWh
A 1.10 0.55 4.00 3.5 N/A
B 1.10 0.55 4.00 2.00 0.03
Notes:

  1. The limits included in this table apply only to those engines designed and built to meet the European Transient Cycle.
  2. Standard A refers to the maximum allowable limits for engines and new units produced until June 2014. These limits will be tested using the test method European Transient Cycle.
  3. Standard B rovides the maximum allowable limits for engines and new units produced from July 2014. These limits will be tested using the test method European Transient Cycle (CET).

Manufacturers may choose to certify gasoline and gaseous fueled vehicles with GVW up to 6,356 kg (14,000 lbs) on a chassis dynamometer over the FTP-75 cycle. The table below summarizes emission standards for chassis-certified vehicles.

Emission Standards for Chassis-Certified Heavy-Duty Vehicles (3,857kg ≤ GVW ≤ 6,350kg)
Standard GVW NMHC
(g/km)
CO
(g/km)
NOx
(g/km)
HCev
g/test
A 3,857 – 4,536 kg 0.285 3.418 0.807 3.0
4,537 – 6,356 kg 0.372 4.350 1.243 3.0
B 3,857 – 4,536 kg 0.121 3.977 0.124 1.75
4,537 – 6,356 kg 0.142 4.536 0.248 2.30
Notes:

  1. HCev measurement applies only to gasoline vehicles and LPG
  2. Standard A refers to the maximum allowable limits for new units from the input into force until Standard B enters into force.
  3. Standard B provides the maximum allowable limits for new units produced, provided that there is full availability nationwide Magna gasoline or replacing it with content average of 30 ppm and 80 ppm maximum sulfur. The implementation of this standard shall be 18 months after publication in the Official Journal of the Federation of the notice of full availability throughout the country.

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