RobbertPatrison

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I decided it was time to check out what is hidden behind the plastic of the frunk. Any maintenance - other than refilling wiper fluid - requires removing the frunk hardware. That adds to the shop cost as it takes time:
  1. Unclip the 3 plastic panels, with quite some force. Clips may fall off and need to be re-attached
  2. Detach several cover panels to remove 8 screws. Some of the screws did not turn easily due to poor threading: they seem to have been rammed in with oodles of torque on the production line.
  3. The frunk 'bathtub' is remarkably sturdy and heavy. It has thick metal reinforcements. It feels good, but I don't fully get why Ford did not try to save a little weight here.
This is viewed once the 'bathtub' is removed:
MacheUnderTheHood.jpg

Compared to the other EVs and cars I have opened, a few things stand out:
  • The plumbing is a royal mess. It seems as if Ford (+ its contractors) designed and placed the components without giving much thought about how they will be hooked up. Piping makes weird detours as a result. Compared to a Tesla MY, the MME has 3X more hoses and 3X more fluid according to Munro. That is a huge difference.
    It looks bad, but is it that bad? A large number of connectors increases the chance of leaks and adds a lot of weight. On the other hand, rubber hoses are cheap and off-the-shelf pumps are cheap. They can be repaired much easier. Looking at this, repair seems quite doable.
  • Given that the front motor is just 50kW, this seems quite large and bulky for what it does. The equipment in my old Chevy Bolt cranked 3X the power out of a hood area that is much smaller. It seems little effort was spent on compact design.
  • If you look down in the hole, the frunk could easily have been 3 inches deeper. The clumsy plumbing at the bottom could easily be moved out of the way. I wonder why this was not done.
  • The radiator fan blows against the frunk bathtub. This must be a hot place in summer.
  • I see 4 electric fluid pumps and a quad valve scattered on the bottom. More on that later.

I spent a little time decoding the mess of tubes that cool and heat. First, there is the motor and electronics coolant loop:
Screen Shot 2022-04-29 at 19.20.46 .jpg


This is a single large daisy chain loop that is cooled by the radiator. So large that it needs two push-pull pumps in series. There are two operational modes:
  1. L1 or L2 Charging, in which case the onboard AC charger produces up to 800Watts of heat. The heat is pushed through the DC/DC converter, the rear motor, and the front motor. Since the motors are not running, they do add additional heat.
  2. Driving, in which case most heat comes out of the rear motor and inverter (and the charger is off). The rear motor has an oil heat exchanger with its own oil pump. The front (non-GT) motor is water cooled only.
IMHO there is nothing really wrong with this setup for motor cooling. The battery and cabin loops, however, are another story. There are loads of pipes. It took me a while to make a good schematic:

Screen Shot 2022-04-29 at 19.21.15 .jpg



There are four loops that interact in intricate ways.
  1. Cabin heater loop: cabin pump->PTC heater->cabin heater core->diverter valve-> cabin pump
  2. Battery chill fluid loop: battery pump-> HV battery -> proportional valve -> chiller -> battery pump
  3. Battery refrigerant loop: compressor->condenser->valve->chiller evaporator->compressor
  4. Cabin cooling loop: compressor->condenser->cabin evaporator core->compressor
Each of these loops can be controlled independently. This means that the MME can cool and heat the cabin independently and at the same time (e.g. for defrost).
The MME can switch off the chilling of the battery and only cool the cabin. But it cannot chill the battery without also cooling the cabin. In practice that is probably OK.

All EVs share the AC compressor for both battery and cabin cooling. But the really odd design choice was that Ford decided to share a single PTC heater between the cabin and the battery as well. Most other EVs have a separate PTC heater in the battery loop. After all, PTC heaters are cheap and small.

This PTC heater sharing ik the MME adds a lot of messy plumbing. When heating the battery the diverter valve connects the two loops into one big one like this:
Screen Shot 2022-04-29 at 19.21.30 .jpg


The loop is: cabin pump->PTC heater->cabin heater core->diverter valve->battery pump-> HV battery -> proportional valve -> diverter valve-> heater pump. (!!)
In this heater mode, the refrigerant valve will be off, and the battery proportional valve feeds the fluid into the diverter valve.
It does mean that the cabin heater will always be on in case the battery needs to be heated. If the car is just charging, the cabin fan will be off so little heat energy will be lost there. When driving, some heat will be sent into the cabin by the blower. If this is undesirable, it could fire up the compressor to mix in some cooling.

It is a little odd that the PTC heater is just 6kW while it needs to service the cabin and the battery in parallel. That seems a little weak, but apparently, it works out OK even in cold climates. The small Chevy Bolt had an 8kW cabin heater plus a 2kW battery heater.

Overall, the heating and cooling system still works fine in practice. If you don't take the frunk apart you will be blissfully unaware of its messy complexity. Perhaps that is the reason why the frunk is covered so well.

 
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xinlitik

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Epic job.

Maybe the shared low watt PTC is why some people in bitter cold (eg canada) have trouble staying warm
 

homerj31

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This is a nice breakdown, thanks for sharing!
 

machme

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I decided it was time to check out what is hidden behind the plastic of the frunk. Any maintenance, other than refilling wiper fluid requires removing the frunk hardware. That adds to the cost as it takes time:
  1. Unclip the 3 plastic panels, with quite some force. Clips may fall off and need to be re-attached
  2. Detach several cover panels to remove 8 screws. Some if the screws did not turn easily due to poor threading: ,: they seem to have been rammed in with oodles of torque on the production line.
  3. The frunk 'bathtub' is remarkably sturdy and heavy. It has thick metal reinforcements. I don't fully get why Ford did not try to save a little weight here.
This is viewed once the 'bathtub' is removed:
MacheUnderTheHood.jpg

Compared to the other EVs and cars I have opened, a few things stand out:
  • The plumbing is a royal mess. It seems as if Ford (+ its contractor) designed dand placed the components without much thinking about how they will be hooked up. Piping makes weird detours as a result. The Ford engineer in the Munro video admitted that that did not come out well. Compared to a Tesla MY, the MME has 3X more hoses and 3X more fluid according to Munro. That is a huge difference.
    It looks bad, but is it that bad? A large number of connectors increases the chance of leaks and adds a lot of weight. On the other hand, rubber hoses are cheap and off-the-shelf pumps are cheap. They can be repaired much easier. Looking at this, repair seems quite doable.
  • Given that the front motor is just 50kW, this seems quite large and bulky for what it does. The equipment in my old Chevy Bolt cranked 3X the power out of a hood area that is much smaller. It seems little effort was spent on compact design.
  • If you look down in the hole, the frunk could easily have been 3 inches deeper. The clumsy plumbing at the bottom could easily be moved out of the way. I wonder why this was not done.
  • The radiator fan blows against the frunk bathtub. This must be a hot place in summer.
  • I see 4 electric fluid pumps and a quad valve scattered on the bottom.

I spent a little time decoding the mess of tubes that cool and heat. First, there is the motor and electronics coolant loop:
Screen Shot 2022-04-29 at 19.20.46 .jpg


This is a single large daisy chain loop that is cooled by the radiator. So large that it needs two push-pull pumps in series. There are two operational modes:
  1. L1 OR L2 Charging, in which case the onboard AC charger produces approx. 800Watts of heat. The heat is pushed through the DC/DC converter, the rear motor, and the front motor. Since the motors are not running, they do not produce heat.
  2. Driving, in which case most heat comes out of the rear motor and inverter (and the charger is off).
There is nothing really wrong with this setup for motor cooling, IMHO. But the battery and cabin loops are another story. Ther are loads of pipes and it took me a while to make a good schematic:

Screen Shot 2022-04-29 at 19.21.15 .jpg



There are four loops that interact in intricate ways.
  1. Cabin heater loop: cabin pump->PTC heater->cabin heater core->diverter valve-> cabin pump
  2. Battery chill fluid loop: battery pump-> HV battery -> proportional valve -> chiller -> battery pump
  3. Battery refrigerant loop: compressor->condenser->valve->chiller evaporator->compressor
  4. Cabin cooling loop: compressor->condenser->cabin evaporator core->compressor
Each of these loops can be controlled independently. This means that the MME can cool and heat the cabin independently and at the same time (e.g. for defrost).
The MME can switch off the chilling of the battery and only cool the cabin. But it cannot chill the battery without also cooling the cabin. In practice that is probably OK.

All EVs share the AC compressor for both battery and cabin cooling. But the really odd design choice was that Ford decided to share a single PTC heater between the cabin and the battery as well. Most other EVs have a separate PTC heater in the battery loop.

This PTC heater sharing adds a lot of messy plumbing. When heating the battery the diverter valve connects the two loops into one big one like this:
Screen Shot 2022-04-29 at 19.21.30 .jpg


The loop is: cabin pump->PTC heater->cabin heater core->diverter valve->battery pump-> HV battery -> proportional valve -> diverter valve-> heater pump. (!!)
In this heater mode, the valve will be off, and the battery proportional valve feeds the fluid into the diverter valve.
It does mean that the cabin heater will always be on in case the battery needs to be heated. If the car is just charging, the cabin fan will be off so little heat energy will be lost there. When driving, some heat will be sent into the cabin by the blower. If this is undesirable, it could fire up the compressor to mix in some cooling.

It is a little odd that the PTC heater is just 6kW while it needs to service the cabin and the battery in parallel. That seems a little weak, but apparently, it works out OK even in cold climates. The small Chevy Bolt had an 8kW cabin heater plus a 2kW battery heater.

Overall, the heating and cooling system still works fine in practice. If you don't take the frunk apart you will be blissfully unaware of its messy complexity. Perhaps that is the reason why the frunk is covered so well.
Great breakdown of the components and function. What model year/job number is your car? I remember some article mentioning that Ford was reducing some of that convoluted plumbing with the newer builds.
 


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RobbertPatrison

RobbertPatrison

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Great breakdown of the components and function. What model year/job number is your car? I remember some article mentioning that Ford was reducing some of that convoluted plumbing with the newer builds.
Mine was built late February 2022. There is no sign that Ford has reduced the plumbing yet. Doing so would require quite a lot of changes to both hardware and software, and possible new cold weather testing. I suspect that they will stick to this until a major technical overhaul of the front front. However convoluted, it works. The engineering effort is likely spet better elsewhere.
 
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RobbertPatrison

RobbertPatrison

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Amazing job! I just made one edit to your labels to more accurately describe one part!

IMG_20220510_220215.jpg
Haha. Indeed: the 12V battery is a little small. That is probably to save cost and weight, but that will wear out the battery quicker. The small capacity also means that if you get stranded with a High Voltage battery failure, things may get pretty dicey quickly. After the 12 V battery drains dead, doors cannot be opened, or the car cannot be shifted from park.
 
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Eugene

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Mine was built late February 2022. There is no sign that Ford has reduced the plumbing yet. Doing so would require quite a lot of changes to both hardware and software, and possible new cold weather testing. I suspect that they will stick to this until a major technical overhaul of the front front. However convoluted, it works. The engineering effort is likely spent better elsewhere.
"The engineering effort is likely spent better elsewhere" Like removing the tailgate kick-away feature. My Mach E was built in Feb 22 as well, looks like we both just missed out on this, being it was discontinued Jan 22.
 
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RobbertPatrison

RobbertPatrison

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"The engineering effort is likely spent better elsewhere" Like removing the tailgate kick-away feature. My Mach E was built in Feb 22 as well, looks like we both just missed out on this, being it was discontinued Jan 22.
They probably removed that because of the parts shortage. A pity, but I am not missing that feature much. It is also not much engineering work to leave out the module.

Rewiring the cooling system is another dimension in terms of engineering change. If you look at other cars: the Chevy Bolt’s drivetrain and cooling is almost completely unchanged since 2017. The Volt V2 had a different drive train that the first Volt, and GM probably regretted that effort as it was a dead end. Tesla is the only company that does more design changes under the hood while keeping the bodywork the same.
 

ripperAZ

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Dude. You’re freakin MacGyver of da Frunk
You should change your screen name
I
I had both a premium and a GT and I took the Frunk out and looked at that mess and decided I didn’t want to know anymore ….kind of like you know how they make hotdogs. You never wanna go on a tour of a sausage factory if you like sausage

The Ford optimist in me is expecting my 2022 models that are on order to have that all cleaned up right🫥🤥🥵😤🤬🤯

Jes sayin…
 

homerj31

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It is a great breakdown of the frunk and related systems. As you noted it is disappointing that Ford did not use resources to clean up or improve some of cooling/heating systems of the car and just kept the tried and true ice methods. I was hoping moving to the MachE they would simplify more of the car systems, doesn't look like this is the case. This is one of the man reasons I decided on a select vs getting a GT. I was not comfortable spending the difference on a car that is close to a beta design. I expect Gen 2 or 3 to be a big leap forward.
 

Eva

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Any chance you can access the parking sensors on the bumper this way?
 

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Dude. You’re freakin MacGyver of da Frunk
You should change your screen name
I
I had both a premium and a GT and I took the Frunk out and looked at that mess and decided I didn’t want to know anymore ….kind of like you know how they make hotdogs. You never wanna go on a tour of a sausage factory if you like sausage

The Ford optimist in me is expecting my 2022 models that are on order to have that all cleaned up right🫥🤥🥵😤🤬🤯

Jes sayin…
Yeah, I agree... Maybe MacGyver's Daddy!
 

JimmyMachE

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Each of these loops can be controlled independently. This means that the MME can cool and heat the cabin independently and at the same time (e.g. for defrost).
The MME can switch off the chilling of the battery and only cool the cabin. But it cannot chill the battery without also cooling the cabin. In practice that is probably OK.
Great analysis, thanks.
Does it mean that on a fast highway trip directly after HPC session on a cold day the HV battery will not be cooled at all if you run cabin heating at the same time? Or car will enforce cabin cooling if some temperature limit was reached in the HV battery pack and HV battery requires cooling?

 

 
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