Chevrolet Bolt EV Coolant System Loops

Hello, I'm professor John Kelly and this is the  WeberAuto YouTube channel. In this episode we are   going to look at the three separate cooling  systems on the Chevrolet Bolt EV but before   reducible there are two Corrections I need to  make to my previous video on the high voltage   system components I stated that the high voltage  battery heater would not activate during DC fast   charging in cold weather I was wrong on that  it does activate it draws around 2,000 watts   or two kilowatts of power as it is activated  and of course those two kilowatts of power   are subtracted from the energy that actually goes  to charge the battery that heater stays on until   about 65 degrees Fahrenheit then it shuts off  the other thing that I need to correct it's not   really a correction but I've forgot one harness  for the high voltage system this harness has a   different part number and is wired differently  if you have DC fast charge or not so let's take   a look at what this harness is and where it goes  and then we'll get into the cooling system loops   so this is the DC fast charge charge receptacle  from the Bolt EV and I mentioned in the previous   video there's a solenoid motor in here that will  activate a lock so that when you have your core   charge cord plugged in it will not let you unplug  it until the high voltage DC is down to a safe   level well in order to control this solenoid motor  there's a harness that needs to be connected but   this harness has two functions the first function  in the orange wiring is for the J 1772 this round   upper portion of the connector to allow the AC  voltage applied from your charger to connect   to the onboard charger module here there's  a AC in connector right here that I never   hooked anything to so on this harness the orange  portion of the harness is going to plug in right   there and that's our AC in then it gets converted  to DC and goes out and charges the battery on the   level 1 and level 2 charging on this end of the  harness the orange harness it of course plugs in   to the charge receptacle for the AC voltage when  you plug that in the level 1 and level 2 charging   now both this fast charge receptacle and the non  fast charge receptacle have to have some way to   connect the AC voltage to the onboard charger  module over here and that's this orange harness   but if you have the fast charge receptacle here  then there's a black harness right here that has   to come and plug in to allow for control of this  solenoid lock here for the charge cord so if you   have DC fast charge this black harness portion  of this cable here is different than if you don't   have the DC fast Church so when I bought this  DC fast charge it did not come with this other   harness and I thought oh it's the same harness  we'll just plug it in but then I got looking at   the wiring diagrams and the and the pins here  and I discovered that it's a different harness   as well so in my quest to convert our Bolt EV to  a DC fast charged if ur n't and then you'll need   the the under hood black low voltage harness that  is also different that connects to our junction   block which is also different there underneath the  hoods so ok now let's look at the cooling system   components for cooling the electronics and the  motor so all of these parts right here the motor   the inverter the onboard charger the accessory  power module they are all cooled by one of the   three cooling systems on this Bolt EV now to make  things easier to understand I'm going to remove   all the high voltage wiring that I've already  connected up so that that's not in our way of   viewing the cooling system so let me get that  removed next okay as you can see I've removed   all of the high voltage electrical connectors  I've also removed the air conditioning system   compressor this AC compressor is not used as  part of this cooling system loop however it is   used as part of the battery cooling system which  we'll look at next but for this cooling system   here the official name of it is the hybrid /  electric vehicle electronics cooling system   and this cooling system is going to have coolant  running through the single power inverter module   the accessory power module the onboard charging  module and then the drive unit and then out to the   radiator through a coolant pump where the coolant  temperature is monitored by an on-board computer   there's a cooling fan variable speed cooling fan  and active grille shutters on the front of the   vehicle all part of this cooling system so let's  build it let's put all the hoses and pieces on   here and take a look at it all right there are  two interesting things about the coolant hoses   on the Bolt EV one is they are labeled as to where  they connect so this is SPI M in that's the single   power inverter module and this one has our ad for  radiator so that that's nice so you know which end   of the hose goes where and and you'll see that  that's a beneficial thing since there's a lot   of hoses on this on this vehicle the other thing  is these hose clamps right here they appear to be   super glued to the hose just on the bottom here  so if I come in and relieve the tension on that   clamp right there I cannot take it off of the hose  it's attached back here and I've have removed one   of them and it's some sort of adhesive I don't  know what it is so in a way that's nice because   it holds the clamp in place but when you go to  remove these and you think you're just going to   undo the clamp and pull the clamp back it doesn't  work that way you got to move remove the hose and   clamped together which means that when you put  these back on you have to put the holes and the   clamp on at the same time and you better use some  coolant for lubrication in there on those dry   hoses as you're trying to put that in otherwise  you're not going to get it on let's start with   this first hose that goes from the radiator to  the single power inverter module to cool it all   right I've just got a little cup of coolant right  here I'm going to use for lubrication this is the   spi M in all of these parts are labeled with  the OL for out and I for in or they're actually   labeled in and out like on the drive unit down  below here so this is the SPI M in there's the   eye right there for the in so coolant that has  already been cooled in the radiator comes into   this hose and goes into the single power inverter  module where it cools the IGBT transistors and   the diodes and the electronics in here and then  goes out through this hose right here so we have   spi em out and then we have a PM for accessory  power module that's our DC to DC converter up   here and that goes to the inlet of the XS repairer  module and we'll bring that over to the accessory   power module in so next coolant will go from our  accessory power module to our onboard charging   module this also has an additional hose as you  can see right here the small one here that will   go to the surge tank the little radiator surge  tank on the driver's side underneath the hood all right so cool coolant from the radiator goes  into the power inverter module that drives the   motor down here then that coolant goes over  to the accessory power module our DC to DC   converter and then that coolant goes down to  the onboard charging module now the single   power inverter module is going to create heat  when you drive the vehicle otherwise it's a   minimal amount of heat the accessory power  module is the equivalent of an alternator   on any other vehicle and so that's going to be  creating heat all the time that your vehicle is   powered up and you're ready light is on and  then that sends coolant down to the onboard   charger module which doesn't create heat at all  unless you've plugged in your AC charge cord to   the side of the car this is not activated at  all during DC charging so there's basically no   heat created by the onboard charging module  while driving the vehicle then we're we've   got a hose that's going to come down to our  drive unit off of our onboard charger module okay so coolant leaves the onboard charging module  comes down to the drive unit we're in the bottom   of the drive unit which we'll see in the next  video when we disassemble this is a big set of   cooling fins that coolant runs through and right  above that as the hot transmission fluid and it   gets hot because it absorbs heat from this stator  assembly and the rotor as you drive down the road   now we just have one cooling fitting left right  here leaving the electric motor the drive unit   so let's see where that goes this is the surge  tank you've got the little clip right here the   the yellow clip that is where your hood latch  latches in notice this has a 5 psi or a 35 kilo   pascal radiator or surge tank cap on it so this  coolant does not get real hot if 5 psi is all   that's needed to keep the coolant from boiling  that's a fairly low temperature cooling system   so connected to the surge tank is a long hose  that goes down to the drive unit the output of   the drive unit where the coolant will come up  into the surge tank and then it will go down   to an electric water pump here and go out to  the radiator and complete the cycle so let's   get this hooked up here okay we have all of the  cooling hoses connected to everything except the   radiator so let's just do a quick review and then  I'll bring the radiator and the other parts over   here and we'll take a look at those so the outlet  from the radiator which is the inlet to the power   inverter module is right here so cool angles  into the inverter module leaves the inverter   module goes to the accessory power module or DC  to DC converter where then it leaves and goes   down to the onboard charging module where then  it leaves and goes down to the drive unit that   propels the vehicle then that coolant comes  up to our surge tank where we can check the   fluid level by the way this coolant needs to be  changed every five years or 150,000 miles that   is the service interval on this coolant system  on all three cooling systems alright then that   coolant goes down to an electric water pump the  outlet of this pump then connects to the inlet   of the radiator okay here is the radiator itself  you can see this this hose right here is the hose   that would connect to our water pump outlet  so that hose right there is going to connect   right there and sit there and then on the other  side the outlet of the radiator is right here   and that would connect to our inverter module  hose which I do not have clocked correctly it   needs to be about right there so let me fix the  orientation of this inverter module hoes they   do have alignment marks on them but this one  had two and I wasn't sure which one it was but   now the hose is up higher to match the radiator  outlet just like that all right while we are here   looking at this radiator this radiator is only  for this electronics loop that we're looking at   and it has a temperature sensor built-in right  here that the hybrid powertrain control module   number two under the passenger seat monitors  and then controls a variable speed cooling fan   that would be right here on the on the backside of  the radiator that fan has two bolts one bolt right   here and the other one up there and two clips one  there and one there that allows it to just slide   in place here's the cooling fan assembly it has  a three wire connection right here I believe it's   a variable speed yes it is sealed brushless  that says a variable speed brushless cooling   fan that would go on the back of this radiator as  we're looking at it here all right the last piece   of this cooling system are these active grille  shutters there's a right hand side and a left hand   side and they can be controlled individually by a  motor pack that's underneath this cover right here   there is an electrical connector underneath the  the active grills where this grill motor module   will communicate over the Lin bus to the hybrid  powertrain control module the purpose of the   active grille shutters is to improve aerodynamics  when extra cooling is not needed so these will   close these apparently only have two positions  open or closed there's no in-between from what   I've read I could be wrong there but from what I  can see they're either open or closed the service   information description of this system says that  you may have to drive the vehicle for as much as   13 minutes above 25 miles an hour before they'll  even begin to move it also tells us that in cold   ambient temperatures these shutters will remain  closed now these active shutters are positioned   about midway down your bumper behind the darker  grill area and they will either allow air to go   through this radiator or not okay so this wraps  up one of three cooling system loops on the Bolt   EV this one once again is just for the power  electronics and the drive unit now we at the   next cooling system that we'll look at is for the  battery the rechargeable energy storage system is   called has its own cooling system and heating  system that is totally separate from this has   nothing to do with this radiator or this all of  this plumbing that we just put together at all so   let's take a look now at the second cooling system  the one for the rechargeable energy storage system   or the battery as we refer to it okay our second  cooling system is called the hybrid electric   vehicle battery pack cooling system it also heats  the coolant that goes through this battery I have   separate videos on the complete disassembly and  reassembly of this battery and you can see the   cooling plates down underneath these five battery  packs in those videos but on here on the front of   the battery we have a coolant inlet and we have a  coolant outlet and that coolant needs to be heated   when the battery is too cold and it needs to be  cooled when the battery is too warm so that we   can keep the battery in the optimum temperature  range for maximum efficiency so let's take a   look at the components of this battery pack  cooling and heating system okay the cooling   system for the battery pack here begins with the  air conditioning system compressor and so we have   our voltage DC Inlet we have our own built-in  inverter that drives a three-phase a variable   speed electric motor inside the compressor here  to drive the compressor the inlet is going to   bring in the low-pressure vapor from the battery  chiller and from the evaporator inside of the   passenger compartment the outlet is going to  push out pressurized high-pressure vapor that   goes to the condenser in front of the radiator  and we'll take a look at that condenser here   in a few minutes so for now let's get these air  conditioning hoses connected okay this first set   of air conditioning hoses has a connection to  the condenser in the front of the radiator and   then it has a connection to the battery chiller to  cool the coolant that goes through the battery so   let's get these connected first okay next we will  connect the battery chiller so this is the battery   chiller and basically it's a mini evaporator now  everybody with an air conditioning system in their   car has an evaporator anyway and just like the  evaporator that cools the air in your passenger   compartment this evaporator is going to cool the  coolant that goes through the battery itself so   if this coolant is too hot heat will be removed  from the coolant through this evaporator so the   air conditioning compressor sends high-pressure  vapor out to the condenser where it condenses   into a high-pressure liquid where then it comes  to this thermostatic expansion valve where it   creates a restriction changes into a low-pressure  liquid where heat is added to it or it absorbs   heat evaporates and high or low pressure vapor  then goes out of the larger outlet pipe here that   low-pressure vapor has absorbed the heat from  the coolant and then that goes back out to the   compressor where it's compressed and ran back to  the condenser where it's condensed into a liquid   loses its heat and the heat from the battery is  transferred to the condenser and then radiated   out into the air so many evaporator here where we  have a high side high-pressure liquid coming in   and a low side low pressure vapor going out that  has absorbed the heat from the battery coolant   so let's connect this up next by the way this has  one hose that connects to the surge tank for the   battery which is on the passenger side under the  hood and then it has a very long hose right here   and goes all the way to the high voltage battery  itself so we'll just dangle this hose over the   back of the the bench for the moment to connect to  the battery all right the next pipes here are the   ones that go from the chiller to the evaporator  inside the passenger compartment and it's just   like this other evaporator I described except it's  much much larger I also want you to see for those   of you who are familiar with air-conditioning  systems this is the pipe within pipe system   where the returning low-pressure vapor that  might still have some liquid in it going back   to the compressor where it's rammed through the  high side high temperature high pressure pipe to   heat it up and evaporate it even more if there was  any liquid left so that no liquid gets back to the   air conditioning system compressor because you  can't compress and liquid you'll break the a/c   compressor so it's a it's a very unique very cool  design this pipe within a pipe system and that's   been going on for several years this is the first  time I've actually had one out of the vehicle to   where I could show anyone but it's a it's a neat  system so we have our high side pressure port   right here we hook gauges up and our low side  pressure port right here this sits right on top   of the battery chiller and then the two lines from  the air conditioning compressor come in right here a lot of pieces coming together here there's  still more for this battery cooling system okay   next we're going to bring in our electric water  pump the surge tank and the rest of the coolant   hoses we have a refrigerant system that cools the  coolant going through the chiller coming back from   the battery and then we also have antifreeze the  GM Dexcool 50-50 mix of antifreeze and deionized   water going through cooling hoses with the  surge tank and a water pump so let's bring   those in next okay so here's the surge tank  for the passenger side of the vehicle under   the hood with its electric water pump right here  and then the hose that goes back to our battery   coolant heater before it goes into the battery  itself so let's connect this up next okay I've   now connected the inlet to the chiller to the  surge tank coolant will then go down through   the surge tank into the pump where it's pumped  over to our 2000 watt battery coolant heater the   battery coolant heater has an outlet that goes  to the inlet of the battery and then it has an   inlet right here from the water pump itself the  condenser has a connection right here the upper   hose from the air conditioning compressor outlet  is high-temperature high-pressure vapor that then   goes into the condenser condenses into a high  pressure a little bit lower temperature liquid   that then is fed to our chiller so let's look  at the evaporator next this is the evaporator   assembly it has built into it a receiver dryer  assembly that to my surprise is serviceable   there's a plug in the bottom of this that you can  take out it has a seal that needs to be replaced   and then the the desiccant bag the dryer portion  that's in here can be replaced without having   to replace the entire can answer assembly on the  other side of the condenser we have the fittings   there the connection fittings to the two pipes  from the air conditioning compressor so this would   sit right here with the two pipes connecting  right there just as we talked about and then   of course this is in front of the radiator for  the first cooling system that we looked at for   the power electronics on this vehicle and then  the cooling system fan is behind that so the   battery does not have a radiator instead it uses  the air conditioning system condenser to radiate   heat out into the out into the air so I'm going  to move this condenser out of the way so we can   look at the rest of the components and review  overall system operation so the job of the air   conditioning system compressor in relation to the  battery is to cool the coolant that goes through   the batteries so the coolant that goes through  the battery has its own surge tank under the   right-hand side of the hood the passenger side  of the hood when you open it up that coolant has   a pipe that goes down to an electric water pump  that then feeds it over to in back of the drive   unit underneath the vehicle the battery heater the  battery coolant heater and that goes to the inlet   of the high voltage battery and then goes through  the battery all this cooling plates and everything   and comes back in on this other pipe right here  where it comes in to the battery chiller and if   the coolant is too hot then the heat transfer into  the refrigerant of the heat from the coolant goes   into the refrigerant then goes back up on the  suction side of our air-conditioning compressor   and repeats the cycle and transfers that heat  to the condenser out into the air so we cool the   battery by removing the heat from the coolant that  goes through the battery and transferring that   into the air-conditioning system and radiating  it out into the the air as you drive and operate   the vehicle so two separate systems here involved  in cooling the battery and then we have of course   a battery heater back here the 2000 watt battery  eater that does come on for both AC and DC quick   charge I know we stopped heating the battery  around eighteen point three degrees Celsius or   around 65 degrees Fahrenheit but I don't know how  what temperature we start cooling the battery I do   know that when the battery is being charged with  your plug-in charger that the air conditioning   compressor through the chiller and the the  water pump is operating to keep the battery   cool because of course the battery heats up while  you are charging and unlike the Nissan Leaf that   tells you in the owner's manual not to charge the  battery while it's hot you do not have to do that   with the Chevrolet Bolt EV and any other liquid  cooled battery because the air conditioning system   compressor will cool the battery while you charge  it alright just a couple more things and then   we're finished with this coolant loop this air  conditioning system as I mentioned in the in the   video on the high voltage system components uses a  special refrigerant the are 1 2 3 4 YF refrigerant   a very expensive refrigerant that refrigerant  requires on this vehicle a special p OE oil   when I took these parts off these air conditioning  system pipes and hoses off I lost oil out of these   and so there is an oil compensation procedure  you have to go through to add a certain amount   of oil depending on what parts have been removed  or replaced the oil comes in a foil bag here and   it tells us to prevent moisture contamination the  oil must be used within two hours of removing from   this sealed foil bag so the oil is hygroscopic  and will absorb moisture out of the air so keep   that in mind if you ever do any service work  then it calls for p OE oil okay so this is the   second cooling system which is really kind of two  systems in one on the Bolt EV the third system is   for the coolant that goes through the heater  core to control the passenger compartment air   temperature now I've received a lot of comments  from viewers of my other videos wondering why   they even had a coolant heater for the heater  core and wondering why we couldn't just use the   heat off the battery or the power electronics  as the heat for the passenger compartment and   at first I wondered myself and then suddenly I  realized well if you want to be able to control   the temperature in the passenger compartment this  gives you the best option because you can turn the   heat way up or way down by turning the heat up  by increasing the temperature of the coolant in   the heater core you will warm up the passenger  compartment very quickly without warming up the   battery if this was a shared system we would  not want the passenger compartment coolant   temperature to be affecting the battery coolant  temperature and I realized there's switching and   mixing valves that can be involved there but I  think on this system here that's probably why   although I don't know they have a separate coolant  heater for the the heater core so let's go take   a quick look at the third coolant system on the  Bolt EV the heater coolant heater okay so under   the hood here we have our last cooling system loop  we have a surge tank with a hose that goes down to   an electric water pump that then pumps coolant  into our cabin heater coolant module where then   the hose goes over and under and you can see  those two hoses right there we've got the inlet   to the heater core right there and the outlet  right there coming back to the surge tank while   we are here you can see right back there is the  thermostatic expansion valve for the evaporator   for the air conditioning system inside the vehicle  all right so this is a real simple cooling system   loop just a surge tank a water pump the heater  the hoses and the heater core inside the passenger   compartment okay well this has been a review  of the three different cooling systems on the   Chevrolet Bolt EV it's very interesting to see  the the different cooling systems on different   hybrid and electric vehicles now finally next  up I'm going to disassemble the drive unit   electric motor and gear reducer so that'll  be our next video thank you for watching.

Channel: WeberAuto

Views: 107,030

Keywords: Professor, Cooling Systems, Coolant Loops, Chevrolet, NACAT, NATEF, ASE, Weber State Automotive, Weber State University, CAT, GM, Bolt EV, #boltev, STEM, Guy in wheelchair, WSU, Air Conditioning, Battery Cooling, Thermal Management, John D. Kelly

Id: _ILkLUE3Zxc

Length: 32min 4sec (1924 seconds)

Published: Tue Dec 11 2018