• Emissions

Emissions

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Introduction#

SUMO includes the following emission models:

• HBEFA v2.1-based: A continuous reformulation of the HBEFA v2.1 emissions data base (open source);
• HBEFA v3.1-based: A continuous reformulation of the HBEFA v3.1 emissions data base (open source);
• HBEFA v4.2-based: A continuous reformulation of the HBEFA v4.2 emissions data base (open source);
• PHEMlight, a derivation of the original PHEM emission model (model is open source, but full data sets are only commercially available);
• PHEMlight5, the V5 version of PHEMlight supporting deterioration emission model (model is open source, but full data sets are only commercially available);
• Electric Vehicle Model: an electricity-consumption model by Kurczveil, T., López, P.A., Schnieder.
• MMP Electric Vehicle Model: an electricity-consumption model by Kevin Badalian from Teaching and Research Area Mechatronics in Mobile Propulsion (MMP), RWTH Aachen University.

Literature on the Models and their implementation can be found at the DLR electronic library (https://elib.dlr.de/89398/).

Using Models#

All models implement different vehicle emission classes. These classes can be assigned to vehicles by using the vehicle type attribute emissionClass. If the model has different classes, the definition has the form emissionClass="<model>/<class>" e.g. HBEFA3/PC_G_EU4. If the model has only one class (for instance the Electric Vehicle Model), the <class> can be omitted in the input and will show up as default in the output. There is one special model Zero which does not generate emissions or energy consumption at all.

Available emission classes can be found within the emission model descriptions (HBEFA v2.1-based, HBEFA v3.1-based, HBEFA v4.2-based, PHEMlight, PHEMlight5). The current default model is HBEFA3/PC_G_EU4 (a gasoline powered Euro norm 4 passenger car modeled using the HBEFA3 based model).

Pollutants / Measurements covered by models#

model	pollutant / measurement
	CO2	CO	HC	NOx	PMx	fuel consumption	electricity consumption
HBEFA v2.1-based emissionClass="HBEFA/..."	x	x	x	x	x	x	-
HBEFA v3.1-based emissionClass="HBEFA3/..."	x	x	x	x	x	x	-
HBEFA v4.2-based emissionClass="HBEFA4/..."	x	x	x	x	x	x	x
PHEMlight emissionClass="PHEMlight/..."	x	x	x	x	x	x	(x)
PHEMlight emissionClass="PHEMlight5/..."	x	x	x	x	x	x	(x)
Electric Vehicle Model emissionClass="Energy"	-	-	-	-	-	-	x
No Emissions emissionClass="Zero"	-	-	-	-	-	-	-

PHEMlight and PHEMlight5 generate electricity consumption values only if the data files for battery powered or hybrid vehicles are available (which are not part of the free data set).

Outputs#

Pollutants emitted by the simulated vehicles can be visualised using sumo-gui or be written into output files, both by sumo and sumo-gui. The following output can be used:

• trip information: In combination with the emissions device, the tripinfo output contains the sum of all pollutants emitted / fuel consumed during a vehicle's journey. To record emissions for all trips add the options --tripinfo-output and --device.emissions.probability 1.0. Alternatively, you can configure emission recording for selected vehicles using generic parameters.
• edgelane emissions: These output files contain the pollutants emitted at an edge / a lane, aggregated over a variable time span
• emission-output: Unaggregated emission values for every vehicle and time step
• Color vehicles by emissions: This can be used to show the emissions for each vehicle during each simulation step
• Color lanes/edges by emissions: This can be used to show the emissions for all vehicles on a lane during each simulation step (or for the whole edge in Simulation/Meso).

Standing vehicles#

A vehicle can have either a foreseeable stop on its route or stop at a junction or in a jam. In both cases it will still produce emissions / consume energy as long as the motor is running. For planned stops SUMO will switch off the engine immediately if the duration is longer than 300s (configurable via the vehicle type generic parameter <param key="shutOffStopDuration" value="300"/> with a value in seconds).

The automated start/stop also for unplanned stops is not enabled by default but can be set using the vehicle type generic parameter <param key="shutOffAutoDuration" value="20"/>. This expects a value in seconds and will switch off the engine automatically if the vehicle does not move for longer than the given time.

Coasting vehicles#

A rolling (combustion driven) vehicle which does not accelerate actively (coasting) will not consume fuel because the engine gets switch off automatically in this case. All PHEMlight and HBEFA models use a threshold depending on the current speed, acceleration and slope to determine whether the vehicle is in this regime and set all emission values to zero. The value depends of course also on the characteristics of the vehicle such as mass and front area. For details see the code of PollutantsInterface::Helper::getCoastingDecel.

Further Interfaces#

The tool traceExporter.py converts SUMO's fcd-output into files that can be directly read by the PHEM application. A tutorial on generating trace files (including PHEM input files) using this tool is available.