California Air Resources Board

Over the years CARB has conducted field studies and hosted workshops pertaining to heavy-duty engines/vehicles. The following provides a summary of CARB's reports and workshops.  

CARB Workshops

Selective Catalytic Reduction Workshop for New Diesel Engines

CARB held a workshop concerning selective catalytic reduction for new diesel engines on July 20, 2010.

Durability Demonstration Workshop for New Diesel Engines

CARB held a workshop concerning durability demonstration and deterioration factors for new diesel engines on March 24, 2010. The workshop covered topics regarding New Emissions Standards, Use of New Emission Control Technologies, Engine Durability Program / Generating New DFs and Certification Issues.

In addition, the Carry Across (CAC) table and Sensor Table were first introduced at the Durability Demonstration Workshop.  

The workshop applies to the following engine categories:

• On-Road CA-Medium-Duty Engines (MDE)
• On-Road Heavy-Duty Otto-Cycle Engines (HDOE)
• On-Road Heavy-Duty Diesel Engines (HDDE)
• Off-Road Compression-Ignition Engines (OFCI--Tier 4i / Tier 4)
• Others (HD Hybrids & Special Cases)

CARB Reports

ARB Heavy‑Duty Vehicle SCR Technology Field Evaluation

The California Air Resources Board (CARB) staff conducted field investigations into the implementation of 2010 model year (MY) on-road heavy‑duty diesel (HDD) engines equipped with Selective Catalytic Reduction (SCR).  The investigations included: (1) two surveys of diesel exhaust fluid (DEF) availability within the State of California, (2) a survey to determine whether truck operators driving 2010 MY SCR-equipped trucks on California roadways have tampered with SCR components or are not using DEF, (3) an examination of the types and effectiveness of SCR driver inducements employed on 2010 MY HDD vehicles, and (4) an examination of the emission impacts of HDD SCR-equipped vehicles when DEF has been depleted, diluted or the SCR system has been tampered with. 

ARB Heavy‑Duty Vehicle SCR Technology Field Evaluation - Second Study

CARB staff conducted a second field study in 2011/2012 similar to the first study but with new heavy‑duty diesel (HDD) engines tested. The investigations included (1) a follow-up survey of diesel exhaust fluid (DEF) availability with the State of California, (2) roadside inspections to determine whether truck operators driving Selective Catalyst Reduction (SCR) equipped trucks on California roadways have tampered with SCR components or are not using DEF, (3) a re-evaluation of driver inducements on two SCR-equipped 2010 model year (MY) Cummins engines evaluated in the first study where error in programming and part malfunctions were found, (4) a continued evaluation of 2010+ MY NOx control strategies including an examination of the types and effectiveness of SCR driver inducements employed on SCR-equipped trucks, and (5) an examination of the emission impacts of HDD vehicles.