Understanding Coolant Flow in a Tesla

let's take a quick look at the four different paths for coolant flow in a Tesla with a heat pump system we are looking at screen recordings in the service mode from the Tesla Model 3 and Y on the left and the Plaid Models S and X on the right the flow of coolant is controlled by an 8-way valve called the octovalve is located on the supermanifold contains a Powertrain pump a battery pump and on the Model S and X there is an additional Chiller pump and a radiator pump there are two separate coolant Loops a Powertrain Loop and a battery Loop these Loops can be put in series with each other or in parallel with each other the super manifold has a liquid cooled condenser (LCC) that can transfer heat energy from the refrigerant to the coolant it also has a chiller that can transfer heat energy from the coolant to the refrigerant there is a radiator to transfer heat energy from the air to the coolant or from the coolant to the air the Model S and X Plaid have an extra large radiator with dual fans notice that we also have temperature and flow rate sensors at the powertrain Loop Inlet and the battery Loop Inlet we can also monitor the pump RPM the fan RPM and the individual temperatures of the components in the powertrain Loop and the battery Loop now let's take a look at the different modes of operation and the flow path for coolant in each mode the first mode is called series mode and we put the entire powertrain coolant Loop in series with the battery coolant Loop for maximum cooling of the cabin and the high voltage battery and the powertrain notice that the flow rate on the Model 3 and Y over here on the left is 18 liters per minute and on the Model S and X Plaid is 28 liters per minute the next mode is called series radiator bypass mode and the octovalve positions itself so that coolant no longer goes through the radiator heat energy is transferred from the battery into the coolant and then into the refrigerant cabin for heating in the next mode the octovalve is positioned so that the powertrain Loop and the battery Loop are running in parallel with each other this allows for cabin Heating and Battery powertrain cooling the next mode is called ambient Source mode and the powertrain Loop and the battery Loop are put in series with each other and the chiller and the radiator are also put in series with each other this allows for heat energy from the air to go into the coolant and then into the refrigerant and then into the cabin it also allows heat energy from the powertrain Loop components to be transferred into the high voltage battery there's actually one more mode of coolant flow and that is off where both coolant pumps are shut off and the air conditioning compressor is run to try to generate heat in very cold temperatures in this heat pump system as usual if you feel that you have benefited from this video please consider a donation to our automotive department there is a link at the bottom of the video description text well that's it for today I will see you next time