16 February, 2013

How long does it take to warm an engine up?

From time to time in some car or other forums, pops up a question of this sort...

How long does it take to warm an engine up?

Most of the answers are reasonable but lack any concrete data. Here I provide, as reference, some data for Renault Clio III 1.2 TCe 100.

At the time of the experiment, the car was less than an year old, at about 10 000 km, with all original parts. The numbers were collected from the OBD-II port via ELM327 Bluetooth type adapter and Torque Pro (OBD 2 & Car) for Android.
  • ambient temperature about 0 °C
  • air humidity almost 100%
  • city terrain (50 km/h speed limit) with no congestion, (just one slow guy in front of me for a while), 
  • AC on
For better understanding, some relevant parameters were also monitored i.e. engine RPM, speed and turbo boost.


In summary:
It took about 13 minutes and 8 km to fully warm the engine coolant without rushing. The engine is small and probably one can see that the temperature increase is smaller while the engine is idling (on the graph - shortly after the 2 km mark). The thermostat opens at 89 °C first, then drops to 79 °C and converges with attenuating oscillations between 80 and 84 °C