Radiator Air Block

[sandange]

What's Wrong with this Picture?

A member from The Quebec EV forum (AVEQ forum) decided to do a test in order to preserve and help boost cabin heat.

This blocking the grill approach is often used on Ice trucks and cars.
I have serious doubts about this action for an EV.
So what's wrong with these pictures?

Scroll down to the posting with the photos posted by "adam"
http://menu-principal-forums-aveq.1...-proprietaire-d-une-I-Miev-tp38457p39024.html

The text translation from French is
(Quote) For my part, I'll do a test this year to see if blocking the front grill will assist cabin heating
There must be a release agent and you need to block the small holes before applying the foam
The can of foam that I used was cheap but was not worth much to produce a bubble-free mold.
So I had to cover the open grill shape with Black Duck tape.
I added double-sided tape to be sure I did not lose on the road.
It's not perfect, but acceptable to validate the concept .
We see a positive improvement, but I'll wait for several cold days in line row to quantify the difference. (end Quote)


Open to your thoughts....

 

[jray3]

Other than as an aerodynamic aid, I think that his grill blocking plug won't help. The motor coolant radiator fan is controlled via a temperature sensor, so it won't run unnecessarily. I don't know whether the coolant pump cycles on and off while driving. Though the i-MiEV uses a conventional heater core, it does not use the motor coolant that flows through the radiator. The heater loop has a separate pump and reservoir, and the heater core can be isolated from outside air by turning the center console HVAC knob to recirculation. This requires the use of air conditioning or cracking a window for effective windshield defrosting. I'm convinced that for my rainy climate, drying the warm cabin air via the air conditioner on recirculate with some reheating is more efficient than heating up the much colder and wetter outside air for defrosting purposes, but I haven't documented the Canion data.

Yes, cold outside air at 100% relative humidity may still contain less moisture than warm cabin air, so my approach varies based on the weather, but in general I find that the air conditioning compressor dries the windscreen much faster than heating up cold humid air, and I think it uses less energy. Optimal HVAC and defrosting algorithms are surely a challenge worthy of Mitsubishi, given their espertise in small air conditioning systems. Anybody who feels like doing the enthalpy calculations gets a tip o my hat.

FWIW- I've been running an upper grill block on our Odyssey van for years, including a summer trip to Yellowstone NP.
https://www.dropbox.com/s/jjgi1fmp1blip7b/Odyssey Aero Comparo.JPG?preview=Odyssey+Aero+Comparo.JPG
(Yes, I removed the bug shield after an initial comparison to baseline.)
Never an issue with overheating, but the engine warms up faster and still stays locked in between 181 and 184 degrees water temperature, so I'm tempted to move up to a 190 degree thermostat. It also cools down more slowly during wintertime parking.

 

[PV1]

Blocking the grill won't do much except risking overheating the motor (I know it doesn't produce nearly the amount of heat as an ICE, but I can easily get it over 90 F in 10 F air). It may help reduce heat loss through the firewall, but so would a bit of insulation.

I haven't paid much attention to the circulation pump while driving, but during charging it cycles based on time, not temperature. Putting the car in Park almost always activates it.

Now, if he combined the coolant and heater loops (like I want to), then blocking the radiator drastically changes the scope of things.

 

[sandange]

Thanks for your input
This helps explain that we have different COOLING circuits on our vehicles.

This brings up some questions
So from what I understand in effect we have several cooling circuits

1 for the motor - is this liquid cooled
1 for the inverter (charger) is this liquid cooled
1 is the AC unit to cool the battery during fast charging

Which of these loops are tied into the radiator and what advantage or disadvantage would restricting air to the radiator have?
My fear is that restricting cooling to these units might cause damage to them.

Heating - Not tied into the radiator
Separate closed loop heating circuit

 

[PV1]

Close, but not quite.

1. There is a closed loop that goes from the heater to the front reservoir, then to the heater core. This is dedicated to cabin heating and doesn't touch the radiator.

2. There is a closed loop that cools the charger/DC-DC converter, MCU, and electric motor. This is the coolant loop that goes through the front radiator, circulation pump, and rear reservoir.

3. The battery pack (for cars equipped with the cold weather package, quick charge package, or premium package, listed as Battery Warming System) uses forced air from the cabin HVAC system to heat the battery during extreme cold charging (below 5 F) and cool the battery (during quick charge). This is in conjunction with a fan mounted inside the battery pack (which is heard for 5 seconds after plugging in on cars equipped with this system).

Blocking the radiator would reduce cooling to the HV components and have minimal effect on cabin comfort and greatly increase the risk of overheating the powertrain.

If I can find the diagrams from the service manual, I'll update this post with them.

 

[databeestje]

You don't want to block the radiator which is used solely for the engine and power electrontics in rear of the car. It's not just the motor.

What you want to do is insulate the heater tank which is sitting in the breeze behind the front hood. And if you have the time, insulate the hoses and the PTC heater hanging in the breeze on the bottom of the car against the steel chassis(!)

http://iserv.nl/files/pics/imiev/heaterinsulation/

I've cut various pieces of 10mm thick adhesive thermal insulation foam in required size with the adhesive side outwards (because almost nothing glues to PP or PE). I then assembled the pieces using duct tape. After assembling this you can just slide it over the tank and then wrap a single tape piece around the rear to keep it into place.

What's left to do is add a top piece with a round hole for the filler cap, but I didn't have time for it since I needed to go.

The sides are the largest pieces at 13,5 (width) by 12cm (height) so it becomes a shroud for the hose on the bottom as well. The shape is bit awkward and not all the sizes are entirely correct but you get the idea from the sketch. The 5,5 width on the bottom and the 3,5 from the bottom up are about correct. You'll have to get the angle correct by holding it next to the side of the tank.

You need 2 sides, and if you use adhesive foam you need to cut 1 part mirrored.
You need 1 5x9cm piece for the top front
You need 2 5x11cm pieces for the top sides
You need 1 15x9cm piece for the front
You need 1 4,5x12cm for the left rear (not 4,5x8)
You need 1 1x12cm for the right rear (not 1x8)

Below are the pictures for the construction, you need to make a small cut (not through) at the 2 folds in the front part so that it's easier to make the bends.
You keep a gap of about 8mm between the top and bottom part so that it basically slides over the sides of the tank and stays in place that way.

 

[sandange]

PV1 - Thanks for confirming my concerns
Restricting air to the radiator would reduce the effectiveness of the cooling .....
to key electronic components

Does the air conditioning unit that cools the air to cool battery via forced air use the radiator ?

This puts them at risk of overheating & damage as well.

databeestje - Thanks for sharing your heater circuit insulation photos . I did a complete heater circuit insulation on my 2012 Miev but when I traded up to y 2014 Miev, I opted to skip this work & expense and go straight to a diesel liquid heater addition which I greatly appreciated these last few day at temperatures of -25C ( -13 F )

 

[Phximiev]

How effective is the insulation? Can you feel the difference in the interior and the effect on range?

 

[PV1]

Yes, sorry. There is a condenser in front of the coolant radiator. Both radiators are stacked, so the air coming through the bumper flows through both.

I'm not sure if there would be an issue with the AC in the winter. Below 40 F, I can't hear or feel the compressor running, so I don't believe it does (or it runs really slowly). In the summer, the fan runs on low speed when using the pre-cooling feature on the remote. Even if the AC does run in the winter, ambient air and the close contact of the radiator would sink enough heat for there not to be an issue (at 40 F, there isn't much thermal energy to move anyway).

As for what's wrong with the picture, potentially ruining the front bumper by spraying foam insulation in the opening is my first pick. Getting a new front bumper isn't easy/cheap, not to mention the aforementioned overheating risk to the HV drive system.

 

[sandange]

My concern for the AC is during fast charging when it kicks in to cool the batteries - even in the winter.

Phximiev - with the insulated heater circuit on our 2012 Miev - we noticed a higher temperature in coming air, but it really did not give us any significant range advantage that we could measure.

 

[Aerowhatt]

I haven't paid much attention to the circulation pump while driving, but during charging it cycles based on time, not temperature. Putting the car in Park almost always activates it.

My 2014 has the cooling pump running anytime the car is in ready mode no matter how hot or cold it is. Additionally, I have never heard the radiator cooling fan come on except when the AC is running. Which suggests that the coolant for the motor etc. rarely (if ever) gets hot enough to cause it to cycle on.

Leading to - Blocking the radiator air is also going to block the AC condenser cooling air which potentially could cause failure of the AC system. Bad Idea!

Aerowhatt

 

[FrostyCanada]

Hello sandange, I suspect that most of these heat saving mods with the exception of your diesel heater produces little to no change in heat being produced by the car.

Does insulating rubber hoses which already dissipate little heat by their very nature make sense in the long run?

Is it even safe to insulating the heating core - i think it might be left uninsulated for a reason?

Maybe the hot water bottle could be insulated, but it too is made of thick plastic and is mostly tucked away from the elements - worth it?

I'm sure Mitsubishi tried most of these mods when developing the car and it probably made no difference in heating performance which is why it never made it from test vehicle to the final production unit.

Food for thought ...

-----------------------------------------

We did our first 60 KM round trip at -24 (going) -14 (returning).

The trip consumed a total of 12 bars (with the heater being set to a reasonable level).

The estimator was still showing a potential of 22 additional KM possible.

The only complaint we have with the car is that the rear wheel have a tendency to slip when leaving from a dead stop on snowy road surface. The anti skid system is very nervous to the point of the car not moving forwards.

Forget about range anxiety it's more like being stuck on a small snowy hill with the car unable to move forwards anxiety. :shock:

Brian

 

[Aerowhatt]

The only complaint we have with the car is that the rear wheel have a tendency to slip when leaving from a dead stop on snowy road surface. The anti skid system is very nervous to the point of the car not moving forwards.

Forget about range anxiety it's more like being stuck on a small snowy hill with the car unable to move forwards anxiety. :shock:

Brian

Had a similar experience backing up out of snowy icy parking in the mountains on Monday. Just turn off the traction control and use the "old" driving skills to get the job done.

Aerowhatt

 

[sandange]

Hello sandange, I suspect that most of these heat saving mods with the exception of your diesel heater produces little to no change in heat being produced by the car.

We had insulated everything in the heater loop, but found it to give very little advantage.

We did our first 60 KM round trip at -24 (going) -14 (returning).
The trip consumed a total of 12 bars (with the heater being set to a reasonable level).

Now you've experienced the full winter exposure and know what you might expect. The worst case is freezing rain the ices up your wind sheild immediately. This forces you to run maximum heat for the defrost and can be a major power drain.

The only complaint we have with the car is that the rear wheel have a tendency to slip when leaving from a dead stop on snowy road surface.
Our cars have a lot of torque so in snowy icy conditions I sometimes use eco mode to help not to slip on take off.

The anti skid system is very nervous to the point of the car not moving forwards.
Yes the anti skid is touchy but can save your but in some situations. If you get a chance and have a safe place - try to make the car skid sideways , you'll experience its full reaction .
If you're ever stuck in a snow bank or parking lot - Aerowhatt said right - turn off the anti skid and go old school.


Brian

 

[databeestje]

Yeah, you can't notice much difference, still need to insulate the tubes and the heater itself, that's for another weekend though. As others commented, it does help with the temperature of the air as more heat reaches the interior. There is a reason people insulate houses and their heating pipes with foam. Well atleast in my house all the radiator pipes have foams around them, get the heat to where you want it without losing too much of it on the way.

What I noticed yesterday evening when I was inserting the top foam part around the filler cap was that the fluid was still luke warm, which was nice, before insulating it was just straight cold. The current outside temperatures are around 3-5C here. The higher the temperature difference to outside, the more heat you lose.

I am considering the diesel heater regardless, but for lack of a garage I'll just wait for the summer to roll by for installing it. I want to keep the electric heater in place, so that would mean I need to install the heater in place of the 12 Volt battery from reading other people' post. Winter has not truely started yet. The last few months it was ~10-15C, which is silly frankly.

 

[Aerowhatt]

I'm finding that the heat used wisely doesn't use as much power as the RR gauge would suggest. perhaps this is why those with better insulated systems are seeing better efficiency of the air heating effectiveness. Without seeing any significant difference in range.

On Monday we drove up to the mountains for a hike in the snow. This iMiEV trip is well worn and documented in different conditions. With some variations it is ~55 miles round trip and 2,600 to 3,400 feet in elevation change (depending on which trailheads we drive to). Monday was cold leaving around midday at 36F outside and even colder when heading back home in the early evening. Generally we return home with canion reading 18% to 24% SOC in summer (some AC) and fall temps (No AC or heat). Since winter has arrived in ernest the end of trip SOC is 19% for the same trip that would yield a 24% SOC in the fall.

Two things of note, the car is garage kept and starts out at 49F or so on a cold day like Monday. I use the remote to heat it up nice and warm (defrost cycle) from the Level 2 before leaving. This is essential to this kind of trip IMO and leaves the heater fluid nice and hot for additional heat trickling in during the drive without using much battery at all. And the battery full and a warm interior to start out.

When returning from altitude the car is very cold after sitting for three to four hours in mid 20'sF environment. After hiking in the snowy mountains you want to be comfortable on the way home. So I use the heat generously. Most of the amps are coming from regen but it doesn't make any difference in the big picture. If I followed the RR gauge as advice I likely wouldn't even make it to the trailhead. Most likely we would turn around worried about getting stranded with a dead battery.

If I needed to, I couldn't see going diesel for heat. More likely I would look at carrying more electrons to make up for the heaters usage. But that's a personal choice not a judgement of anyone else's choices.

Aerowhatt