With a few exceptions, emission standards for new heavy-duty truck and bus engines are based on the European standards. The legislation for China III-V stages—which are based on Euro III-V, respectively—was adopted in 2005 . The emission limits are shown in Table 1.
|China III||ESC + ELR||2.1||0.66||-||5.0||0.10/0.13†||0.8|
|China IV||ESC + ELR||1.5||0.46||-||3.5||0.02||0.5|
|China V||ESC + ELR||1.5||0.46||-||2.0||0.02||0.5|
† For engines with a per cylinder displacement of < 0.75 L and rated speed > 3000 rpm|
a Applicable only to gas engines
b Not applicable to gas engines
c Expected China VI limits 
|At the China I/II stage (not shown in the table), the test was ECE R-49 or the Chinese 9-mode.|
The following provisions apply to emissions of ammonia and nitrogen dioxide:
- NO2 requirements: OEMs are required to report tailpipe NO2 concentration and NO2 increase level if an oxidation catalyst-based aftertreatment system is used, such as DOC, POC, DPF or NAC.
- NH3 slip limit: No limit for China IV. For China V, NH3 slip limit is 25 ppm (peak) and 10 ppm (cycle average).
Implementation dates for the standards are listed in Table 2. The dates generally refer to new type approvals—first registration of existing vehicle models is typically allowed for one more year.
|Standard||Actual Date||Initially Scheduled|
|a Beijing has additional requirements for China IV and China V heavy-duty diesels, see below.|
In 2012, the Ministry of Environmental Protection proposed and solicited comments on a proposal to require China IV and China V heavy-duty vehicles to meet a supplemental WHTC cold-start test requirement for the type approval process that would apply nationwide . Beijing implemented a similar requirement in 2013.
Emission durability requirements, including the engine useful life and the minimum aftertreatment testing periods, are shown in Table 3. The aftertreatment periods according to HJ 438-2008 are mandatory for type approval and production conformity, while GB 20890-2007 provides a guideline to conduct aftertreatment durability testing during product development.
|Category||Useful Life||Aftertreatment Testing|
|GB 20890-2007||HJ 438-2008|
|M1 (GVW > 3.5 t)|
|100,000 km/5 yrs||50,000 km||100,000 km|
|M3 (GVW ≤ 7.5 t)|
N2 and N3 (GVW ≤ 16 t)
|200,000 km/6 yrs||60,000 km||125,000 km|
|M3 (GVW > 7.5 t)|
N3 (GVW > 16 t)
|500,000 km/7 yrs||80,000 km||167,000 km|
The GB 20890-2007 standard recommends that aftertreatment testing be conducted on-vehicle, over the China Heavy-Duty Durability Cycle—Vehicle (C-HDD-V). Alternatively, an engine based durability test can be conducted over the China Heavy-Duty Durability Cycle—Engine (C-HDD-E).
To prevent excess NOx emissions during low-speed, urban driving conditions from some heavy-duty diesel vehicles (HDDVs) type approved to Euro IV and V equivalent standards, the Beijing Municipal Environmental Protection Bureau (EPB) released two new local standards in February 2013. These two standards are supplemental to China IV and V standards and apply to China IV and V vehicles with Gross Vehicle Weight above 3,500kg and registered in Beijing. The Beijing EPB also announced an intention to retrofit existing China IV and V heavy-duty vehicles sold in Beijing prior to implementation of the new standards.
The first of these standards , implemented March 1, 2013, requires China IV and V engines to be tested over the World Harmonized Transient Cycle (WHTC) in addition to the currently required European Transient Cycle (ETC). In Europe, testing over the WHTC is not required until the Euro VI stage. Both cold-start and hot-start tests are required, with results weighted 14% and 86%, respectively. Table 4 provides the WHTC cycle limits for the China IV and V stages. Most of the limit values are equal to the Euro IV/V ETC values except those for NOx emissions.
|China IV||4.0||0.55||1.1||3.7 (3.5)c||0.03|
|China V||4.0||0.55||1.1||2.8 (2.0)c||0.03|
a only gas engines|
b not applicable to gas engines
c ETC cycle limits shown in parentheses
The second standard , implemented July 1, 2013, establishes in-use, complete vehicle Portable Emission Measurement System (PEMS) testing requirements for manufacturers to prove that real-world emissions do not overly exceed the type approval limit values. There are two options that manufacturers can choose from to calculate emission values from PEMS testing: the work-based window method and the not-to-exceed (NTE) method.