Abstract. We present an exploratory study carried out with a new miniature portable
emission measurement system (Mini-PEMS) specifically designed at the
Technical University of Liberec (CZ) for applications on two-wheeler vehicles
owing to its reduced size (45cm×30×20cm) and weight (≈15 kg).
It measures the exhaust gas concentrations of hydrocarbons and carbon mono-
and dioxide with a nondispersive infrared method and nitrogen mono- and
dioxides and oxygen using an electrochemical cell. In addition, the
instrument acquires the engine speed, manifold absolute pressure,
inlet and exhaust gas temperature, geo-localization, and vehicle speed.
The exhaust mass flow rate is calculated from engine and emission data. The
Mini-PEMS was validated on three two-wheelers (one moped and two motorcycles)
against laboratory-grade instrumentation in the Vehicle Emissions Laboratory
of the European Commission in terms of measured concentrations, exhaust
flow, fuel consumption, and mass emission of pollutants. The mean absolute
deviations of gas concentrations were 8 % for HC, 8 % for CO, 13 % for
NOx, and 2 % for CO2, while the mass emissions (which include the
exhaust flow determination uncertainty) were 7 % for HC, 7 % for CO,
9 % for NOx, and 5 % for CO2. An agreement of 2 % was
achieved between the fuel consumption measured in the laboratory and
calculated by the Mini-PEMS. As an application, the instrument was tested on
board the vehicles during on-road trips. The emissions measured on the road
were consistent among repeated runs, with differences between laboratory and
on-road tests much larger than those between the Mini-PEMS and laboratory. We
found similar or larger HC and NOx real-driving emissions and larger CO emissions from
motorcycles and smaller ones for the moped. Considering its size and weight, the
Mini-PEMS proved to be an efficient tool for vehicle monitoring, research
and development and could be tested for in-service monitoring applications
related to carbon monoxide and nitrogen oxides emissions. A tentative
approach to characterize particulate mass and particle number was presented
and compared to the existing filter method and nonvolatile particle number
protocol.