Aeromod nissan leaf improved aerodynamics increased range

[BrockWI]

I can't say if it creates a pocket that catches air or if the air in the space acts as a buffer.

My intention was to slow the air in to the "engine" bay and then in to the car to try to reduce heat loss, not really make it any more aerodynamic.

 

[NeilBlanchard]

A closed "pocket" is nearly as good as a flush cover, aerodynamically.

 

[sklancha]

I am not sure if this is the right thread for my question but I am confident you are the right audience

There are two decisions Nissan made in designing the Leaf, that are intended to make the transition from ICE to EV more comfortable, but in doing so, they decrease the efficiency. What I want to know is if Nissan would/ could undo these ICEy choices:
1. Creep- not a natural behavior for an EV and is a waste of electricity. Can this artificially proframmed phenomena be disconnected/cancelled/removed?
2. Regenerative braking. I understand that it is dialed down to feel less dramatically different, but I would like them to unleash my regen beast. Let my battery suck all that energy up. Why not? This could really improve my mileage potential AND keep me from using my brake pads unnecessarily.

Can a service station tweak these changes into my Leaf or maybe a creative EV engineer or EV owner?
Angel

 

[Slow1]

1. Creep- not a natural behavior for an EV and is a waste of electricity. Can this artificially proframmed phenomena be disconnected/cancelled/removed?
2. Regenerative braking. I understand that it is dialed down to feel less dramatically different, but I would like them to unleash my regen beast. Let my battery suck all that energy up. Why not? This could really improve my mileage potential AND keep me from using my brake pads unnecessarily.

#1 - This is very much a personal preference I can assure you. The "best" solution I know of is having the option to enable/disable this from the vehicle itself (i.e. what Tesla has done). Personally I would have it enabled - I spend far too much time in the school drop-off lanes and traffic. I'm very curious how you determine it is a waste of electricity though...

#2 - Again, would be nice to be custom set. It seems that Nissan is moving in this direction with their "B mode" as well as the economy modes. I'm not sure I want the 'single pedal' driving that some folks appear to desire. There is limited regen for various reasons. In city traffic I rarely exceed the 4th 'dot' of regen. Highway is another thing, but if you are looking for increased range/reduced brake wear driving more 'softly' is going to go a long way (i.e. plan ahead and coast down with regen doing it's thing whenever possible). My understanding is that when you push the brake pedal on the Leaf it increases regen to the max the car can handle before kicking the brake pads into use anyway....

 

[garsh]

I hear ya. But it's not as bad as you think.

1. Creep- not a natural behavior for an EV and is a waste of electricity. Can this artificially proframmed phenomena be disconnected/cancelled/removed?

Creep only occurs at very slow speeds, therefore not a lot of energy is wasted. Once you've come to a complete stop, *and* you're holding down the brake pedal sufficiently hard, then creep is disengaged. So it's really not much of an efficiency loss.

2. Regenerative braking. I understand that it is dialed down to feel less dramatically different, but I would like them to unleash my regen beast.

I wish for this too. I've driven a Model S twice, and I'm reminded of how it could be each time.

Nissan does, however, add additional regen when you press the brake pedal - unlike the Model S. So that's the way to unleash the Leaf's regen beast. There are caveats of course. If the temperatures too hot or too cold, then the programming won't allow much additional regen. But once again, this design decision means the efficiency loss really isn't as bad as it would seem at first.

 

[sklancha]

I didnt know that the creep disengages after we push on the brakes for a bit. If that is so, I suspect it is not a pipe dream that it could be disengaged completely- though you are right that the amount of wasted juice is probably negligible.
As for the regen- are you suggesting that Nissan might be accomplishing the right amount of regen- just using a different technique? That makes me feel a bit better, but it just doesnt seem like I get much regen.

 

[garsh]

As for the regen- are you suggesting that Nissan might be accomplishing the right amount of regen- just using a different technique?

I'm saying that you get additional regen when you hit the brake pedal in a Leaf (I'd like more regen in many situations, but you can't have everything). The easiest way to see this is to put the Nav screen on the "Energy Info" display. You'll see the electric motor gauge showing more regen when you start hitting the brake.

 

[NeilBlanchard]

The VW e-Golf has adaptive creep - if you stop the car and hold the brakes for a few seconds, you can release it and you won't go anywhere (in fact it seems to have a hold function?). If you lightly accelerate, and then let off the pedal, you will continue forward slowly, so you can creep in traffic, etc.

I am fine with driver controllable regen - I want to be able to coast by default, and then ramp up the regen only when it is needed.

Back on topic: lower aero drag means coasting is better, and the lower the drag, the bigger advantage coasting is. If we weren't leasing, I would be doing aero mods, for sure.

 

[minispeed]

I am not sure if this is the right thread for my question but I am confident you are the right audience

There are two decisions Nissan made in designing the Leaf, that are intended to make the transition from ICE to EV more comfortable, but in doing so, they decrease the efficiency. What I want to know is if Nissan would/ could undo these ICEy choices:
1. Creep- not a natural behavior for an EV and is a waste of electricity. Can this artificially proframmed phenomena be disconnected/cancelled/removed?
2. Regenerative braking. I understand that it is dialed down to feel less dramatically different, but I would like them to unleash my regen beast. Let my battery suck all that energy up. Why not? This could really improve my mileage potential AND keep me from using my brake pads unnecessarily.

Can a service station tweak these changes into my Leaf or maybe a creative EV engineer or EV owner?
Angel

Neither of these 2 would increase your range or efficeiency. They just change the way you have to control the car to get the best efficiency.

As mentioned by others the energy used by creep is so small and at very low speeds. This means that if you are doing a lot of creeping then you will probably be in the car for way too long at very low speeds to need anything more than the energy the car has now. If you want to negate the impact of creep when a car in front of you moves but only a small amount don't move your car. Stay on the brakes and only come off them when you are actually moving, not just driving to the next point in stop and go traffic 3m ahead.

Regen. You'll go further if you use less of it. Yes it's better than friction brakes when you need to stop but if you coast earlier when you are coming close to a known stop (ie stop sign) or a possible stop (red light) then you'll use less energy out of the battery. The less energy you take out will be greater than continuing to use energy to maintain speed then later on getting regen back in while coming to that stop. In the case of a red light many times if you coast you'll find it turns green and you accelerate away from a slow speed instead of driving right up to the light using regen then stopping and soon accelerating away from 0. Teslas all regen with the right foot makes it harder to coast (I assume since I haven't driven one), VW groups sail or coast whatever they call it makes it super easy. Blending regen in with the brakes makes some computer glitches show with transition but with proper use you can get the max amount of regen that a right foot only system would provide without actually using the friction brakes even though your foot is on the friction brake pedal.

 

[Slow1]

There are so many ways to engineer this - basically what seems to be missing are options to take advantage of the unique attributes of EVs. In time they will come...

For example, I would like to have a feature that puts the car effectively in neutral when I let off the gas unless I touch the brake (could be adaptive to speed - i.e. mild regen if at low speeds, but coast if over 30mph or something). I find myself putting the car in neutral (via push to reverse at speed) frequently to allow coasting down roads without accidental regen. Would be nicer (and safer perhaps) to have it go into this mode automatically if at speeds unless 'indicated' by touch of brake that I wish to regen/slow the vehicle. I say safer as I realize whenever I manually go into neutral, I have to put it back in drive before I can accelerate - which is a delay that in some case could be critical if I needed to 'pull out' of a situation.

Back to OP and topic at hand - has anyone yet successfully replicated the benefits of the aero mod originally reported here?

 

[minispeed]

I tried the grill block yesterday, just used duct tape and did about 90%. Didn't do A-B-A but the temp on Monday were warmer than Tuesday so I should have got better efficiency on Monday. My usually drive has the way there being more efficient than the way back (more uphill). 45 miles each way, mostly highway, just under 60 is my cruising speed, slower up hill faster down.

So open grill, about 16C, still on my light winter tires.
Way to work 5.3 m/kWh, used some drafting, wasn't planning on doing a compare)
Way home, don't remember the temp but ran the fan (no ac) to keep cool, 4.5

Grill block on, a little cooler, 13C on my way to work, (took 2 small detours to stores), 5.0. On my way home 9C, wanted to run heater lightly but wanted the numbers more. 4.6

Not the best numbers, on the way home that might be one of the best consumptions I've ever had on the highway. In the summer I have got over 6.2 on the way to work using low speed and drafts. There are less trucks coming home at night.

Winter tires are coming off soon and all season 17s will go on. I'll get some base numbers with the 90% tape block, take it off, then put on a more permanent block around 75%. My goal is to put the plate lower in the centre of the grill, block one side year round and block both sides in winter. I'm not a fan of doing proper A-B-A testing because I don't have the time. I just use the same route on multiple days and try to drive as best I can and then compare.

Reverse mud flaps will go on soon too.

 

[GetOffYourGas]

These numbers seem insane to me. How do you get such high efficiency on the highway? I cannot get 4.0miles/kWh on the highway, even keeping the speed to 60MPH. I typically get about 3.5-3.8 going the speed limit (65MPH).

 

[camasleaf]

These numbers seem insane to me. How do you get such high efficiency on the highway? I cannot get 4.0miles/kWh on the highway, even keeping the speed to 60MPH. I typically get about 3.5-3.8 going the speed limit (65MPH).

It must be Km/kWh :lol:

 

[garsh]

These numbers seem insane to me. How do you get such high efficiency on the highway? I cannot get 4.0miles/kWh on the highway, even keeping the speed to 60MPH. I typically get about 3.5-3.8 going the speed limit (65MPH).

Drafting helps a lot.
Also notice that he gets those higher values for the mostly-downhill return commute.
That said, I rarely get above 5.0. But I probably don't draft as close as he does.

 

[minispeed]

These numbers seem insane to me. How do you get such high efficiency on the highway? I cannot get 4.0miles/kWh on the highway, even keeping the speed to 60MPH. I typically get about 3.5-3.8 going the speed limit (65MPH).

It must be Km/kWh :lol:

No I was nice enough to convert for all you. I don't do temp C to F since it's not as simple as opening up the windows calculator. There will be a slight rounding since I just use 1.6 but since the dash isn't that accurate I don't think it matters.

In km the dash numbers were 8.4, 7.9, 7.0, 7.2 (from memory don't have the pad I wrote them down on). The best ever day I referenced was over 10 in km. That was on the mostly downhill part with a truck in front of me doing 60 for over 75% of my drive. My drafts are not NASCAR style. I try to keep 2 car lengths back from the semi.

My wheels helped too, 51 psi Nokian Hakka R2s, advertised as "super low rolling resistance". A number of years ago someone won an eco rally on Nokian winter tires, an older version of what became the R2s and 10.4lb 15 in rims. It's almost a 10lb saving per corner. I also oversize all my tires as a larger tire will usually have better rolling resistance as well as putting less millage on the car, compared to 16s my winters are 2.5% larger so the numbers the computer spits out are with a distance 2.5% shorter than I actually drove. My 17s are actually 5.8% larger (215 55 17). Finally my car is lowered for a bit smaller frontal area. The larger tires compensate so it's about 1/2 in lower than stock.

As far as driving I never try to keep the speed to 60 (just under 100km/hr). I aim to keep that an avg. I let it dip if there no traffic behind me and I'm going up hill. Even slight grades that don't even look like a hill, I'll let it dip as low as 80km/hr which is about 48 mph. I use the energy screen and try to never use more than 20 kW to the motor I also keep the dash screen on the instant km/kWh and try to keep it above 7.5. I'll coast downhill up to 110 km/hr and use regen above that. If I've got a car behind me going up hill I'll usually dip to 90 if there's an open lane for them to pass, no open lane I'll dip to 95. The last trick I use is looking very far ahead when I can and reacting quickly to a slow down in traffic with a coast instead of brakes.

 

[garsh]

Finally my car is lowered for a bit smaller frontal area.

How did you lower your car?

 

[minispeed]

Finally my car is lowered for a bit smaller frontal area.

How did you lower your car?

Tein H-Tech springs from nengun in japan. Cost a bit less than half of coil overs from megan racing. They are ok, rears ride a little harsh, front perfect. Since I put my new conti tires on they feel better but the contis are just at 47 psi now (same that I had stock bridgestone at) and less than the 51 I had my winters on which has been over 75% of the driving I've done on the car so far.

If I was going to do it again I'd go coil over for sure and spend the extra money. Even with my larger tires I still think there's at least 1/4in too much wheel gap. I'd probably go .6in lower if I had coil overs.

 

[Wennfred]

I ordered the mud flaps today on Amazon, 4 pieces $126.00 free shipping, same color as car. Will work on covering up the front grill soon using 4.5" width vertical blind material and 3M clear tape.

Various colors here

http://www.amazon.com/s/ref=nb_sb_ss_i_4_14?url=search-alias%3Daps&field-keywords=nissan+leaf+splash+guard&sprefix=Nissan+Leaf+sp%2Caps%2C241&rh=i%3Aaps%2Ck%3Anissan+leaf+splash+guard" onclick="window.open(this.href);return false;

 

[GetOffYourGas]

These numbers seem insane to me. How do you get such high efficiency on the highway? I cannot get 4.0miles/kWh on the highway, even keeping the speed to 60MPH. I typically get about 3.5-3.8 going the speed limit (65MPH).

It must be Km/kWh :lol:

No I was nice enough to convert for all you. I don't do temp C to F since it's not as simple as opening up the windows calculator. There will be a slight rounding since I just use 1.6 but since the dash isn't that accurate I don't think it matters.

In km the dash numbers were 8.4, 7.9, 7.0, 7.2 (from memory don't have the pad I wrote them down on). The best ever day I referenced was over 10 in km. That was on the mostly downhill part with a truck in front of me doing 60 for over 75% of my drive. My drafts are not NASCAR style. I try to keep 2 car lengths back from the semi.

My wheels helped too, 51 psi Nokian Hakka R2s, advertised as "super low rolling resistance". A number of years ago someone won an eco rally on Nokian winter tires, an older version of what became the R2s and 10.4lb 15 in rims. It's almost a 10lb saving per corner. I also oversize all my tires as a larger tire will usually have better rolling resistance as well as putting less millage on the car, compared to 16s my winters are 2.5% larger so the numbers the computer spits out are with a distance 2.5% shorter than I actually drove. My 17s are actually 5.8% larger (215 55 17). Finally my car is lowered for a bit smaller frontal area. The larger tires compensate so it's about 1/2 in lower than stock.

As far as driving I never try to keep the speed to 60 (just under 100km/hr). I aim to keep that an avg. I let it dip if there no traffic behind me and I'm going up hill. Even slight grades that don't even look like a hill, I'll let it dip as low as 80km/hr which is about 48 mph. I use the energy screen and try to never use more than 20 kW to the motor I also keep the dash screen on the instant km/kWh and try to keep it above 7.5. I'll coast downhill up to 110 km/hr and use regen above that. If I've got a car behind me going up hill I'll usually dip to 90 if there's an open lane for them to pass, no open lane I'll dip to 95. The last trick I use is looking very far ahead when I can and reacting quickly to a slow down in traffic with a coast instead of brakes.

Ah, that makes a lot more sense now. I feel that driving like that in New York would be very dangerous. Or maybe I'm just not dedicated enough? Here the speed limit is 65MPH, and people typically drive 75-80. Letting your speed drop to 48MPH would be a bad idea.

I should take a close look at my tires. I keep underestimating the hit I am taking to efficiency by using cheapo tires. I had to replace the stock tires before my lease was up, so I went real cheap. But I since decided to buy out the lease, and could stand to get some good efficient ones.

I agree that the Leaf is too high. I typically like very low cars, since they handle much better and give you a better connection to the road. I have zero experience in this area - I'll have to dig into it a little more.

 

[garsh]

How did you lower your car?

Tein H-Tech springs from nengun in japan.

I keep hoping to discover a less-expensive way to lower the car a bit.