Negative values for combustion engine torque

[ppb2020]

The current definition of combustion engine torque is as follows:

#
# Current Torque
#
Torque:
  datatype: uint16
  type: sensor
  unit: Nm
  description: Current engine torque. Shall be reported as 0 during engine breaking.
  comment: During engine breaking the engine delivers a negative torque to the transmission.
           This negative torque shall be ignored, instead 0 shall be reported.

It's not clear why a negative value must be ignored. There are situations where the value of negative torque would be useful in some calculations.

Could the datatype be changed to an int16 in order to support negative values? (V4 being a new major versions, it would be the right time for this kind of change.)

[erikbosch]

I see no real problem if it is changed to int16. But then we need to update description as well - I see two options:

• We state that the signal shall report negative torque during engine breaking
• We state the it is a variation point how engine breaking shall be reported - i.e. an OEM may report 0 or actual negative torque.

Feel free to create a PR.

[erikbosch]

Meeting notes:

• Pierre to prepare PR
• Candidate for VSS 4.0

[ppb2020]

Confirming that our sampling showing negative torque for combustion engines was indeed obtained from CAN buses by at least two of our providers, from actual vehicles.

[erikbosch]

Supports negative torque now on master, closing issue