Reduction Gear Oil Change - Benefits for Range

My Nissan Leaf Forum

Help Support My Nissan Leaf Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I get 3,9 miles per kwh on my '20 SV, so 1/3.9 = 0.256 kwh/mile === 256 wh/mile typically.
Without any air resistance (air drag), that figure would probably be around 7 miles per kwh, so let's use 7.
So 1/7 = 143 wh/mile
Energy savings per mile would be 1% of 143 wh/mile ==== 1.43 wh/mile === 0.00143 kwh/mile

Or you could just say I'd get 150 miles from my 40 kwh battery using Nissan Matic S, and that increases to 151 miles on Valvoline ULV thinner oil. Much of the Road Load (power required to drive on level ground with no headwind or tailwind) is from basic air drag, so something around 1 mile advantage in range is the net effect, depending on driving style, city or hiway.
 
voltamps said:
Energy savings per mile would be 1% of 143 wh/mile ==== 1.43 wh/mile === 0.00143 kwh/mile
Starting from 1% savings -- sure.

But I want to be stubborn and think about this *my* way ...
If the gear box friction savings is 0.7 Nm, is it correct to say that is 700 joules of energy savings per km traveled ?
 
voltamps said:
I get 3,9 miles per kwh on my '20 SV, so 1/3.9 = 0.256 kwh/mile === 256 wh/mile typically.
Without any air resistance (air drag), that figure would probably be around 7 miles per kwh, so let's use 7.
So 1/7 = 143 wh/mile
Energy savings per mile would be 1% of 143 wh/mile ==== 1.43 wh/mile === 0.00143 kwh/mile

Or you could just say I'd get 150 miles from my 40 kwh battery using Nissan Matic S, and that increases to 151 miles on Valvoline ULV thinner oil. Much of the Road Load (power required to drive on level ground with no headwind or tailwind) is from basic air drag, so something around 1 mile advantage in range is the net effect, depending on driving style, city or hiway.

Thanks for posting that, it puts everything into perspective. Is there any additional energy saving when cooling the gear oil is mixed in? I mean, all of them (oils) are designed to provide low viscosity at high(er) temperatures. If you have something that is cooling the gear oil to keep it at a certain temperature versus the heat generated by the friction within the system (gears, oil, etc.)?

If anyone has every noticed that on a warm day, you plug in your Leaf to charge. After a while, you hear the cooling pump running. If the coolant is warm enough, you can even hear the fans kick on. All of that uses energy, not sure how much, haven't measured.

Now, if on a warm day. Say you have a nice stretch of highway to just dump the throttle and go 0 to 100 mph non-stop. During that intense acceleration (for a Leaf anyway), if you listen carefully, during some part of that acceleration, you will hear the radiator fans kicks in, loud at high speed. I had to tape a cheap phone to the inside of my Leaf to find out :mrgreen: because during high power usage, it always sounded like another system of motors was kicking in, now I know what it was. So it is possible to really heat up the motor (and gear box too I would guess).

It would seem that the gear box oil, using ULV, as many others have said, in theory, doesn't really gain much (1% extra range by itself). That's why I have a theory that, looked at alone, the ULV isn't producing huge range gains, very small as you can demonstrate by the math. But... it might be part of an avalanche effect within another system of the Leaf (cooling system) that uses a lot more power and thus keeps the temperature just low enough that this more power hungry system doesn't have to switch on (as much) and that's where the extra range savings is coming from. Both in hotter climates because of cooling and cold climates because of heat needed to reach a good viscosity for the oil to function.
 
knightmb said:
It would seem that the gear box oil, using ULV, as many others have said, in theory, doesn't really gain much (1% extra range by itself). That's why I have a theory that, looked at alone, the ULV isn't producing huge range gains, very small as you can demonstrate by the math. But... it might be part of an avalanche effect within another system of the Leaf (cooling system) that uses a lot more power and thus keeps the temperature just low enough that this more power hungry system doesn't have to switch on (as much) and that's where the extra range savings is coming from. Both in hotter climates because of cooling and cold climates because of heat needed to reach a good viscosity for the oil to function.
There is an interesting trade-off going on here since viscosity drops as its temperature increases and the thicker oil warms up quicker.

The specific mass of oil is ~ 0.8 grams per liter, so perhaps 0.7 (?) for these thin oils.
The specific heat is ~ 2,000 joules per Kg*C. So it sounds like LEAF like ranges are not going to heat up the oil to temperatures that require active cooling but a thicker oil will heat up quicker.
 
voltamps said:
I get 3,9 miles per kwh on my '20 SV, so 1/3.9 = 0.256 kwh/mile === 256 wh/mile typically.
Without any air resistance (air drag), that figure would probably be around 7 miles per kwh, so let's use 7.
So 1/7 = 143 wh/mile
Energy savings per mile would be 1% of 143 wh/mile ==== 1.43 wh/mile === 0.00143 kwh/mile

Or you could just say I'd get 150 miles from my 40 kwh battery using Nissan Matic S, and that increases to 151 miles on Valvoline ULV thinner oil. Much of the Road Load (power required to drive on level ground with no headwind or tailwind) is from basic air drag, so something around 1 mile advantage in range is the net effect, depending on driving style, city or hiway.

Which makes this thread laughable!
 
Owning an EV, or any car really, makes me think back to Physics. I'm a Halliday-Resnick 2nd Edition person myself, early 1980's requirements for engineering school. That textbook has been improved since, and I need to check out the continuous improvements made by Walker after 1990. Cool subject! The better you know that book, the better an engineer you are, no kidding, it is the foundation.
51xyCsZaJqL._SX258_BO1,204,203,200_.jpg
 
knightmb said:
Is there any additional energy saving when cooling the gear oil is mixed in?
Cooling the gears would make the oil stay thicker (more viscosity), and thicker oil loses even more energy. I say don't cool the oil too much since you actually want it to get as thin as possible, within limits.

knightmb said:
....the fans kick on. All of that uses energy, not sure how much, haven't measured.
Fans are wasting energy. Those fans are getting rid of the heat during charging. It's not much lost energy. Certainly losses though. Gone.

On that same note, I was once curious as to how much heat losses you get charging & discharging an Li-Ion battery. I think I found you only lose around 2% lost to waste heat, depending on the amps going in or out, but usually not much.

knightmb said:
..... avalanche effect within another system of the Leaf (cooling system) that uses a lot more power....
That's true to some extent. Think about it from the viewpoint of how much power (watts) has to flow on the wires feeding the motor. If the gearbox is more efficient, less watts are needed on those wires, less waste heat is generated. A small amount less. Same goes for better lower resistance tires, it results in the need for less watts on those wires & less heat too.

In fact, maybe the best way to look at all this is to use some hard facts we have. The Road Load, which has been measured on Leafs many times. Road Load includes the gearbox internal frictional drag, and all the dissipative energy losses up into the motor's internal windage losses.

Therefore, Road Load is great to tell us how many Watts must flow out of the battery itself !!!

Road Load at 60 MPH is 489 Newtons.
So that is 26.8 meters/second x 489 N = 13.1 kW power being drawn out of the battery at 60 mph.
Road Load from a 2013 Leaf (similar in a 2020 Leaf) from https://inldigitallibrary.inl.gov/sites/sti/sti/5737951.pdf page 5.

Routing 13.1 kW power through the gearbox, 1% of that would be 0.131 kW savings using low visc oil. Like burning a 100 watt light bulb waste at 60 mph.
 
lorenfb said:
Which makes this thread laughable!
My approximations don't quite cut it, that's true. That part is laughable. There is nothing like simply trying it on the road like what knightmb & estomax are doing.

The engineering paper that showed about a 1% loss from using thicker oil kind of nails the issue, done in a real transmission. The challenge for physics modelers is to include & know about enough things to simulate it right.

.......knightmb had a good point about there being some (small??) cascading savings effect, when your battery has to provide less watts flowing out to overcome all the losses in the Road Load. Anything saved is less you have to cool with pumps and fans.
 
voltamps said:
My approximations don't quite cut it, that's true. That part is laughable. There is nothing like simply trying it on the road like what knightmb & estomax are doing.

I'm about to have a 3rd person help with this. They have a 2015 Leaf, so for the past weeks, we've been recording driving routes, temperatures, efficiency numbers, tire pressure, etc. to help establish a baseline. Then we are going to make the switch from the Nissan Matic S to the ULV (same brand I used) and then do the same recording of numbers for a few weeks to see if any change happens, even if a small, can be recorded. The easy part of having Nissan do some of the data recording via the car link has run into the same issues others have been having with 3G modems, seems to be having connection issues. Going to stick with LeafSpy as much as possible though, easier to work with in spreadsheets. :mrgreen:
 
SageBrush said:
If the gear box friction savings is 0.7 Nm, is it correct to say that is 700 joules of energy savings per km traveled ?
The 0.7 Nm is a torque, not quite a force. Energy joules is proportional to a dimensionless radian angular displacement x torque which varies by how much radius the tire has for 1 km of travel.

If we knew it was 0.7 Newton-meters torque savings, then to get total energy saved over 1 kilometer, multiply 0.7 Newton-meters torque times the number of radians of rotation in 1 km. (Assuming you mean 0.7 newton-meters as measured at the wheel.)
Instead of going through a radians per km conversion, :
Easiest way to calculate energy over 1 km (1000 meters) is to divide the 0.7 nm by 0.3 meters tire radius to get 2.33 Newtons force on the road savings.
Then 2.33 Newtons x 1,000 meters = 2,330 joules = 0.00065 kwh saved over a km.
 
knightmb, Does LeafSpy display watts or kilowatts coming out of the battery as you drive?
((( I really need to get LeafSpy. I've had my Leaf for several months now and still have not bothered with it.)))

If LeafSpy (or some other ELM327 bluetoothed OBDII to a phone app or laptop) can display the power (watts or kilowatts) flowing from the battery, then you could take your friends thick-oil Leaf, get a reading, maybe do it a couple of times over a couple routes, maybe three, then change to Valvo ULV, and get the same readings, compare.
Same temperatures, tire pressures same, hoping for no difference in headwinds or tailwinds.
If some wind, then take readings in both directions and average the two directions.

knightmb said:
I'm about to have a 3rd person help with this. They have a 2015 Leaf, so for the past weeks, we've been recording driving routes, temperatures, efficiency numbers, tire pressure, etc. to help establish a baseline. Then we are going to make the switch from the Nissan Matic S to the ULV (same brand I used) and then do the same recording of numbers for a few weeks to see if any change happens, even if a small, can be recorded. The easy part of having Nissan do some of the data recording via the car link has run into the same issues others have been having with 3G modems, seems to be having connection issues. Going to stick with LeafSpy as much as possible though, easier to work with in spreadsheets. :mrgreen:
 
OOPS -- let me try again.
First, am I correct in saying that the measurements are at the input shaft ?

Power = torque * 2 * pi * rps


1500 rpm = 25 rps
Then
a torque reduction of 0.7 Nm is a power savings of
0.7*2*pi*15 = 109 watts

Am I getting close ?
 
Back to an earlier post that mentioned ATF heating ...

It takes ~ 2500 joules to heat the ATF one C, and
about 1100 joules of heat are added per second.

So it takes 25/11 = 2.3 seconds of driving to increase the fluid 1C
Call it 27 degrees C a minute

Or 2 - 3 minutes of driving to reach 100 C without heat transfer out of the gear case.
 
SageBrush said:
First, am I correct in saying that the measurements are at the input shaft ?
By that, do you mean the half-shafts' torque at the wheel connection? It can be wherever you say it is for this example, AFAIK. Isn't this just notional?
I'm not sure what input shaft, maybe you're talking about the motor's output shaft, which is the input shaft to the gearbox.


SageBrush said:
Power = torque * 2 * pi * rps
1500 rpm = 25 rps
Then
a torque reduction of 0.7 Nm is a power savings of
0.7*2*pi*25 = 109 watts
Am I getting close ?
Yes, thats it, because there are 2pi radians per revolution so the units work out. And based on newtons, seconds, meters, watts, joules being consistent units to calculate energy and power.

I just loaded LeafSpy Lite (free) and it works on my BAFX brand ELM327 bluetooth thingie on the OBDII port.

Did you get the 0.7 Nm torque delta difference from the motor's output shaft readout in a better version of LeafSpy?

My "lite" version only shows me battery module voltages as far as I can tell. Guess its worth getting the full version, maybe even the Pro one, to see if it gives battery power output in kW or Watts. The kW on the dashboard would be OK, but would rather have a number to get a delta difference. This would be good to do if changing tires and we wondered if the new tires have better or worse rolling resistance.
 
voltamps said:
Did you get the 0.7 Nm torque delta difference from the motor's output shaft readout in a better version of LeafSpy?
I pulled it from the article you posted earlier (with a little rounding and averaging.)

To recap:
About a 10% reduction in power use in the gearbox,
The gearbox is ~ 10% of motive power **
So overall, the thinner oil results in ~ 1% additional range.

Yes, input shaft to the gearbox.


**
That actually surprises me. IIRC the Prius gear set is under 5%
You might find this article on the Prius drivetrain interesting
https://www.osti.gov/servlets/purl/921783
See page 33 of the pdf, page 25 on the printed page
 
SageBrush said:
I pulled it from the article you posted earlier (with a little rounding and averaging.)
OK, I see the 0.7 Nm off one of the graphs in there. I was mostly looking at the percent efficiency vs. torque input graph next to it, but either works.
That 0.7 Nm difference (loss) from the thick vs. thin fluids is "spin loss", lightly loaded in a double planetary gearset auto tranny, although it might be our simpler gearbox could have 109 watts of dissipation, more likely less, not sure here.
 
voltamps said:
knightmb, Does LeafSpy display watts or kilowatts coming out of the battery as you drive?
((( I really need to get LeafSpy. I've had my Leaf for several months now and still have not bothered with it.)))

I think mine was set for watts (vs kilowatts), but I think pressing the number can change it between many different units.
 
knightmb said:
I think mine was set for watts (vs kilowatts)
OK, I was wondering if LeafSpy would even have Power (watts) at all. It does, which makes perfect sense! My el cheapo free LeafSpy Lite doesn't. .........The left side dashboard display (on my 2020 at least) does have those semi-circular power bars that I could take a picture of with my phone when I drive past a known landmark on a road at a certain speed.

With cruise control on, I'll try to take a snapshot of the power-bars on the dash, or from LeafSpy Pro.
Then repeat to see if I can get the same picture.

What would really be cool is if we could command a fixed power output, and then just look to see what MPH speed that gives us.
 
I was looking at the app store entry for LeafSpy, the problem is the screen shots are just too small a resolution, you can't see it all the stuff it shows. I can run mine and take a few screenshots to better show what LeafSpy Pro can show for readings. Years ago, I just started doing some random presses to see how many different readings I could switch it around too.... :lol:

Edit: Added some screenshots... you can customize the screen data so you can tell mine is heavily customized :lol:

High Throttle...
gvTs7nf.jpg


High Regen...
s2mrCTa.jpg


Driving Data Logs...
xgKwoC7.jpg

jGPHMTd.jpg
 
Back
Top