Questions about the emissions calculations API

[romulus.pasca]

Hi Guys, I did some tests with the PTV emissions API today, and I do have some questions:

1. Which are the fields used to calculate emissions based on HBEFA32?
As far as I check I notice that besides the waypoints, weight and emission standards no other attributes seem to influence the computation. I did set up some data such load, engine details, year of manufacture but none looks to change the computation.

2.Which are the fields used to calculate emissions based on EN16258DEFRA2014?. It looks to me that engine fuel consumption and biofuel ratio are used in calculation, but no other engine properties, neither weight, load, year of manufacturing or emission standard have any part in computation.

3. When we do the EN16258DEFRA2014 computation when shall we use the VEHICLE_SPECIFIC_AVERAGE_FUEL_CONSUMPTION instead of one from FLEET_SPECIFIC_AVERAGE_FUEL_CONSUMPTION, ROUTE_SPECIFIC_AVERAGE_FUEL_CONSUMPTION?
If we want to use one of the FLEET_SPECIFIC_AVERAGE_FUEL_CONSUMPTION, ROUTE_SPECIFIC_AVERAGE_FUEL_CONSUMPTION options, how can we come with specific values such fleet specific or route specific fuel consumption?

Thank you, Romulus Pasca, trucknet.io

[Bernd Welter]

Hello Romulus,

these are very good questions! Let me try to answer them:

1. How to determine properties that refer to emission calculation
There are many vehicle properties (and vehicle engine properties) that have an influence on emission (but also on other aspects such as the route itself, toll, truck attributes and preferred routes.

Check the comment: the relevance categories are listed here

Look into the Vehicle Profile and Engine. For those properties that are linked to the Emission calculation we mention the reference in brackets:

scheenshot from the "Engine" properties

Be aware that the default vehicle is a "VW Golf VI".
Provide your sample request to me and we can have a look at this. The challenge is to understand which parameters are related to which emission standard. For this it is important to be aware of the difference between factor based approaches (such as EN_16258 / DEFRA_2014) and comprehensive approaches (such as HBEFA). I also created a generic article about this difference.

2. Relevant properties for CEN = EN_16258 and DEFRA_2014: Well, as these two standards are based on the factor based approach the relevant parameters are covered by dedicated emission parameters contained in the Emission Scenario where you can specify values for the specific fuel consumption. For the comprehensive approaches you would have to specify vehicle's technical properties such as engine size, fuel type, weight and so on. The definition of the standard then derives the consumption (and therefore the emission output) from these techncial values.

3.CEN = EN_16258 / DEFRA 2014: when to aply what?
Here's another article that gives you some decision criteria by story versus scenario. I hope this answers the third question. If not let's discuss over there what you would need to be clarified.

Best regards,
Bernd