TY - JOUR
T1 - Testing Method for Electric Bus Auxiliary Heater Emissions
AU - Pettinen, Rasmus
AU - Anttila, Joel
AU - Muona, Tommi
AU - Pihlatie, Mikko
AU - Åman, Rafael
N1 - Funding Information:
This paper is based on measurements performed for HSL Helsinki Region Transport as part of their Helsinki Open Charging System project. The Helsinki Open Charging System project is co-funded by the ELENA Facility, managed by EIB and financed by the European Commission through the Horizon 2020 Programme. Collaboration with HSL is gratefully acknowledged.
Publisher Copyright:
© 2023 by the authors.
PY - 2023/4
Y1 - 2023/4
N2 - Auxiliary diesel heaters are commonly used in all types of vehicles in cold climates and conditions around the world. Electric buses used in public transport utilise diesel-burning auxiliary heaters to provide thermal comfort for passengers under cold weather conditions while maintaining the operational range otherwise reduced by electric heating. However, the downside of utilising diesel burners is that they cause similar exhaust pollutants to conventional diesel vehicles. Because the emission control for auxiliary heaters is lax, the diesel burners typically lack any exhaust aftertreatment (EAT), resulting in potentially high local emissions. As the public transport sectors around the world seem to transit from traditional internal combustion engine-vehicles to battery electric applications, the significance of the emissions caused by diesel auxiliary heaters is continuously increasing. EVs are generally considered zero-emission vehicles but the implementation of diesel burners is evidently conflicting with this concept. Nevertheless, publicly available experimental results from studies around this topic are surprisingly limited. The data of the few available publications are not directly comparable because there is no direct procedure or protocol for determining the exhaust pollutants from auxiliary heaters in real-world conditions at present. As a result, assessing the direct effect of the pollutants caused by electric vehicles utilising auxiliary heaters in the public transport is challenging. This study addresses this problem by introducing two methods for measuring auxiliary heater emissions; first, a field-test method that is applicable for a quick screening of the emissions of multiple heater units; secondly, a laboratory test method for a more detailed emission characterisation in a simulated real-world operation environment. In these experiments, the primarily objective was to study the emissions of the auxiliary heaters, including CO2, CO, NOx and soot. The heater operation was found to be cyclic with numerous start-ups during its typical operation. The cyclic operation resulted in concurrent emission peaks in CO and soot. Measurements of actual operation showed auxiliary heater utilisation rates similar to the controlled measurements, although the whole temperature range of the controlled measurements was not reached in real-world conditions. The measurements conducted during the field screening revealed high variations between emissions of individual units. A further screening of auxiliary heaters would provide a better outlook for the mitigation of their emissions.
AB - Auxiliary diesel heaters are commonly used in all types of vehicles in cold climates and conditions around the world. Electric buses used in public transport utilise diesel-burning auxiliary heaters to provide thermal comfort for passengers under cold weather conditions while maintaining the operational range otherwise reduced by electric heating. However, the downside of utilising diesel burners is that they cause similar exhaust pollutants to conventional diesel vehicles. Because the emission control for auxiliary heaters is lax, the diesel burners typically lack any exhaust aftertreatment (EAT), resulting in potentially high local emissions. As the public transport sectors around the world seem to transit from traditional internal combustion engine-vehicles to battery electric applications, the significance of the emissions caused by diesel auxiliary heaters is continuously increasing. EVs are generally considered zero-emission vehicles but the implementation of diesel burners is evidently conflicting with this concept. Nevertheless, publicly available experimental results from studies around this topic are surprisingly limited. The data of the few available publications are not directly comparable because there is no direct procedure or protocol for determining the exhaust pollutants from auxiliary heaters in real-world conditions at present. As a result, assessing the direct effect of the pollutants caused by electric vehicles utilising auxiliary heaters in the public transport is challenging. This study addresses this problem by introducing two methods for measuring auxiliary heater emissions; first, a field-test method that is applicable for a quick screening of the emissions of multiple heater units; secondly, a laboratory test method for a more detailed emission characterisation in a simulated real-world operation environment. In these experiments, the primarily objective was to study the emissions of the auxiliary heaters, including CO2, CO, NOx and soot. The heater operation was found to be cyclic with numerous start-ups during its typical operation. The cyclic operation resulted in concurrent emission peaks in CO and soot. Measurements of actual operation showed auxiliary heater utilisation rates similar to the controlled measurements, although the whole temperature range of the controlled measurements was not reached in real-world conditions. The measurements conducted during the field screening revealed high variations between emissions of individual units. A further screening of auxiliary heaters would provide a better outlook for the mitigation of their emissions.
KW - auxiliary heaters
KW - electric bus
KW - exhaust emissions
KW - public transport
UR - http://www.scopus.com/inward/record.url?scp=85156124245&partnerID=8YFLogxK
U2 - 10.3390/en16083578
DO - 10.3390/en16083578
M3 - Article
AN - SCOPUS:85156124245
SN - 1996-1073
VL - 16
JO - Energies
JF - Energies
IS - 8
M1 - 3578
ER -