A5005697276- Vehicle emissions and performance
- Air Quality and Health Impacts
- Catalytic Processes in Materials Science
- Air Quality Monitoring and Forecasting
- Atmospheric chemistry and aerosols
- Advanced Combustion Engine Technologies
- Transportation Planning and Optimization
- Energy, Environment, and Transportation Policies
- Electric Vehicles and Infrastructure
- Advanced Battery Technologies Research
- Electric and Hybrid Vehicle Technologies
- Atmospheric and Environmental Gas Dynamics
- Traffic Prediction and Management Techniques
- Vehicle Noise and Vibration Control
- Coal Properties and Utilization
- Brake Systems and Friction Analysis
- Vehicle Dynamics and Control Systems
- Aerodynamics and Fluid Dynamics Research
- Engineering Applied Research
- Hydrocarbon exploration and reservoir analysis
- Methane Hydrates and Related Phenomena
- Image and Video Stabilization
- Smart Materials for Construction
- Aerosol Filtration and Electrostatic Precipitation
- CCD and CMOS Imaging Sensors
California Air Resources Board
2014-2025
Dongguk University
2023
Georgia Institute of Technology
2004-2005
Real-world nitrogen oxides (NOx) emissions were estimated using on-board sensor readings from 72 heavy-duty diesel vehicles (HDDVs) equipped with a Selective Catalytic Reduction (SCR) system in California. The results showed that there large differences between in-use and certification NOx emissions, 12 HDDVs emitting more than three times the standard during hot-running idling operations real world. overall conversion efficiencies of SCR on many well below 90% threshold is expected for an...
Engine and exhaust control technologies applied to compressed natural gas (CNG) transit buses have advanced from lean-burn, lean-burn with oxidation catalyst (OxC), stoichiometric combustion three-way (TWC). With this technology advancement, regulated gaseous particulate matter emissions been significantly reduced. Two CNG equipped engines TWCs were tested on a chassis dynamometer, their measured. Emissions the then compared in previous studies. Stoichiometric TWC was effective reducing of...
Experiments were conducted to characterize the particulate matter (PM)-size distribution, number concentration, and chemical composition emitted from transit buses powered by a USEPA 2010 compliant, stoichiometric heavy-duty natural gas engine equipped with three-way catalyst (TWC). Results of particle-size distribution showed predominant nucleation mode centered close 10 nm. PM mass in size range 6.04 25.5 nm correlated strongly lubrication-oil-derived elemental species detected gravimetric...
Though the current wave of electric vehicles is transforming on-road passenger and commercial vehicle fleets, similar attempts in off-road equipment sector appear to be lacking. Because diverse categories varied applications, electrifying requires significant research development. A successful electrification such can offer an array benefits, including reduced air noise pollution, higher energy efficiency, increased productivity. This paper provides a review state technology electrification,...
Recent tightening of particulate matter (PM) emission standards for heavy-duty engines has spurred the widespread adoption diesel filters (DPFs), which need to be regenerated periodically remove trapped PM. The total impact DPFs therefore depends not only on their filtering efficiency during normal operation, but also emissions and frequency regeneration events. We performed active (parked driving) passive regenerations two vehicles (HDDVs), report chemical composition these events, as well...
Particulate Matter (PM) concentrations near highways are influenced by vehicle tailpipe and non-tailpipe emissions, other emission sources, urban background aerosols. This study collected PM2.5 PM10 filter samples two southern California (I-5 I-710) over weeks in winter 2020. Samples were analyzed for chemical source markers. Mean approximately 10-15 30 μg/m3, respectively. Organic matter, mineral dust, elemental carbon (EC) the most abundant PM components. EC polycyclic aromatic...
The objective of this research was to collect real-world activity data from agricultural equipment that could be considered when informing air quality and incentive programs in California. This included monitoring 208 tractors via either engine hour records or loggers, with 103 these monitored loggers. results showed the average annual hours usage for agriculture declined as a function age/older technology. were 60, 130, 143, 741, 739 h, respectively, Tier 0, 1, 2, 3, 4 tractors. used about...
This work evaluated the nitrogen oxide (NOx) emissions of 277 heavy-duty diesel vehicles (HDDVs) from three portable emission measurement system testing programs. HDDVs in these programs were properly maintained before testing, so malfunction indicator lamp (MIL) was not illuminated. NOx some significantly higher than certification standard even during hot operations where exhaust temperature ideal for selective catalytic reduction to reduce NOx. For engines certified 0.20 g/bhp-hr standard,...
We present a 640 × 480 CMOS image sensor (CIS) with in-circuit bi-directional gamma correction proposed digital-correlated double sampling (CDS) structure. To operate the in CIS, transfer function of analog-to-digital converter can be changed by controlling clock frequency counter using analog CDS. However, CDS is vulnerable to capacitor mismatch, feedthrough, etc. Therefore, we propose digital-CDS method hold-and-go structure CIS. The CIS achieves 10-bit resolution global log-exponential...