Project Objective:
According to the California Air Resources Board (CARB) in 2010, on road heavy duty diesel trucks are estimated to account for up to 28% or 559 tons per day of oxides of nitrogen (NOx) and up to 12% of PM emissions inventory statewide. Truck idling contributes significantly to these emissions. Idling emissions are significant at the port terminals and distribution centers where long waiting hours are required for loading and unloading operations, and at rest areas and traffic stops, among others. CARB has proposed regulation to reduce idling emissions from new trucks starting with the 2008 model year. The regulation requires manufacturers to either meet an emissions standard or have a timer system that automatically shut off the engine after five minutes of continuous idling.
The objective of the proposed investigation is to perform exploratory research and develop several ring-shaped injectors for increased mixing enhancement between the exhaust gases and the injecting agent, for development of a high efficiency selective catalytic reduction, SCR, filter for significant reductions in NOx and PM emissions of idling diesel engines.
Task Descriptions
Task 1. Assessment of Single and Multi-Ring Injectors for Mixing Enhancement (6 months)
Several rings with different injecting holes will be developed. A fully developed pipe flow will be used to assess the performance of the ring injectors. The ring injectors will be placed inside the pipe flow with injecting holes in counter flow, co-flow and perpendicular to the flow (similar to jets in cross flow) conditions. Smoke will be injected at different flow rates through the ring injector from outside connecting tubes for smoke flow visualization. The smoke will be generated using a ROSCO Delta 3000 smoke machine. Strobe lights and/or a 1 watt Argon-Ion laser will be used to illuminate the visualization area. Images of the flow will be recorded using a LA VISION 4Q cross correlation CCD camera. Mixing enhancement of each ring injector will be assessed from the rate of spreading of the jets within the pipe flow, using instantaneous and averaged images from the CCD camera.
The ring injectors with the highest mixing capacity will be selected for further experimentation. The pipe flow will be heated with electric heater and ring injectors will be fed with water and mean temperature and humidity measurements will be performed at different planes across the pipe flow, using various T-type thermocouples and humidity probes. Here the rate of cooling of the flow is an indication of the mixing effectiveness of the ring injector.
Task 2. Development of a SCR system with Ring-Injectors (6 months)
Based on the optimum design configuration(s) developed from task1, a SCR system with ring injectors will be developed. The system will be installed at the exhaust of a Komatsu 6 cylinder 207 horsepower fuel injected diesel engine. The engine is similar to the diesel truck engines serving the ports of Los Angeles and Long Beach. All tests will be carried out at the engine's idling condition. The SCR system will be tested with different injecting solvent including Urea, industrial alcohol and diesel fuel. Exhaust emissions will be measured with and without the injecting solvent, to assess the effectiveness of the ring injector in reducing NOx and PM emissions. The gaseous pollutants will be measured with a portable ENERAC Micro-Emissions Analyzer, Model 500, which is capable of measuring CO, NO, NO2, NOx, and SO2 accurately.
Upon successful completion of the proposed project, proposal for development of an industrial SCR unit with ring injector and an automatic injecting control system will be submitted to appropriate agencies for completion of the system development before commercialization.
Milestones, Dates:
June 1, 2007 – May 31, 2008
Total Budget:
$39,998
Student Involvement:
Two students at 25% effort, 10 months
Relationship to Other Research Projects:
Related to 08-22; part of the goods movement focus area
Technology Transfer Activities:
Project report posted on the website
Potential Benefits of the Project:
Significant reductions in NOx and PM emissions from idling truck engines
TRB Keywords:
CARB, PM, NOx, diesel engines, emissions
