In this study the performance of a monofuel compressed natural
gas articulated truck was investigated under real-world conditions.
To analyze the CNG vehicle due to fuel consumption and exhaust
emissions a representative road-test route was conducted, including
sections with significantly different driving conditions. Moreover,
driving tests on freeway under higher load were carried out.
As experimental equipment, a new ultra compact on-board system
measured the in-car exhaust mass emissions in real time. Every
second, a full dataset of CO₂, CO, HC and NOx emission
rates was provided. The real-world emission measurements are based
on a modal analysis of the emission concentrations in the tailpipe
of the vehicle. The exhaust gas mass flow is calculated from the
air mass flow and the gas components with a real-time reaction
model. In combination with the vehicle speed, the emission rates in
g/s are then calculated in gram per kilometer. Furthermore, the
fuel consumption in g/s or kg/100 km is calculated with the carbon
balance method according to the EU Commission directive
1999/100/EC.
The gained distance related emissions and the derived mean
values are based on the several thousand individual datasets
measured at the drive tests. In order to link the measured exhaust
emission data with geographical information of the road-test route
a GPS tracking was implemented as well.
Additionally, the application of new calculation and
experimental methods in this investigation allowed developing
characteristic maps of the CNG powertrain based on the real-world
measurement data.
