Effect of driving cycles on the particulate mass and number emissions from in-use heavy heavy-duty diesel vehicles

Abstract

With recent emission regulations aiming to cut down emissions by lowering heavy-duty vehicle particulate matter in terms of mass, there is concern regarding particle size being lowered. Nanoparticles have been known to penetrate to the lowest part of the lung, the alveolar region. Serious complications are known to occur when particles in large concentration tend to deposit in the alveolar region. Formation of these particles depends on various factors like engine operating conditions and dilution ratios. This study focused primarily on the particle mass and number emission from various in-use heavy heavy-duty diesel vehicles operating on different driving cycles. Chemical speciation results are also presented to discuss the formation and composition of particles emitted during various cycles. Tests were performed with West Virginia University's Transportable Heavy Duty Vehicle Emissions Testing Laboratory located at Riverside, California. Five vehicles were selected to cover a wide range of model year from 1989 to 2004. All five vehicles were subjected to chemical speciation and analysis conducted by Desert Research Institute. WVU employed the use of the Scanning Mobility Particle Sizer (SMPS) to measure particle size distributions. Regulated gaseous emissions and total particulate matter from the exhaust were sampled from a full-flow CVS dilution tunnel system. A mini-dilution system was dedicated specifically for particle sizing, which samples partially from the raw exhaust. All vehicles were subjected to California's Heavy Heavy-Duty Diesel Truck (HHDDT) schedule which consisted of an idle, creep, transient and cruise mode. Particle size and chemical speciation data are presented only for the idle and cruise modes since the SMPS can measure a size distribution only during a steady engine operation.

Duty Cycle Characterization and Evaluation Towards Heavy Hybrid Vehicle Applications

“…Two example cycles are shown to give the reader a flavor of the trace belonging to the given characteristics. The high-speed cycle on the top left is the cruise3 cycle [5] and the low speed cycle on the top right is the Manhattan cycle [6]. Because these macro values relate directly to equation 10, they are the correct numbers to use for energy use estimation.…”