TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

"Best potential" room for improvement

Discussion in 'Technical' started by emir-t, Jan 22, 2015.

  1. emir-t

    emir-t Member

    Joined:
    Oct 28, 2013
    Messages:
    200
    Location:
    Istanbul
    As you know when ICE engines first came out they weren't as practical and efficient as they were today. In terms of efficiency and consumption, incredible progress has been made with ICE cars. Now we're beginning to see vehicles that consume on the south side of 6lt/100 km(north side of 40mpg)

    My question is, when it comes to electric cars, which are has the best potential for improvement?

    - Lowering motor consumption: Making motors consume less Wh on average for the same job done would make range better with current battery packs, this would be the most desirable improvement.
    - Making batteries denser and denser: I know this is happening as we speak and maybe we could see a 100kWh battery pack for Model S in the future but this would make charging times longer. Not a problem for everyday use but for those long road trips it's kind of an hassle.
    - Getting the batteries to charge faster: This is a solution for those EV skeptics with road trips in mind.

    Thanks for the answers in advance. Cheers;

    --
    Emir
     
  2. Saghost

    Saghost Active Member

    Joined:
    Oct 9, 2013
    Messages:
    3,038
    Location:
    Delaware
    #2 Saghost, Jan 23, 2015
    Last edited: Jan 23, 2015
    The problem with lowering motor consumption is that the types of electric motors used by electric cars are already very efficient.

    The best of them operating in the ideal range convert 95% of the electricity into mechanical movement, and the typical one averages well over 80% over the full operating range.

    That means that a theoretical perfect motor could only reduce consumption by 20% or so. Improvements will continue to happen, but for motors the main improvements will be making lighter cheaper motors rather than note efficiency (companies are undoubtedly looking for more efficient, too - there just isn't much room to make a difference there.)

    Battery density improvement is the thing that will help EVs most, and had been for many years. There are a number of technologies being researched that may lead to large improvements; companies continue to refine the current tech and make small improvements over time.

    A high capacity cheap compact lightweight battery would instantly make an EV a better choice for the vast majority of drivers with no other changes.

    One thing you may not realize is that a lager battery inherently solves the faster charging as well, from a consumer's standpoint at the Supercharger. The limits of rapid charging are based on what the cell can safely accept, and expressed as a multiple of the cell's capacity - meaning a bigger battery of the same design can inherently take a faster charge in absolute terms. (Example: the 85 kWh model S supercharges faster than the 60 kWh car, achieving almost twice the range pretty unit time over the ramp according to Bjorn's video.)

    Tesla is now installing 135 kW Superchargers, but the best current cars can only handle 120 kW, and only for the few minutes that they are charging the lower middle portion of the pack. A notional 100 kWh car off similar technology could take the full 135 kW for quite a bit longer, giving faster charging on the same infrastructure.

    There's a 98% point here, too: once you get enough range to drive for several hours, supercharge during lunch, and drive for several more, anything more becomes moot for the vast majority of drivers while they have Superchargers covering their route. Driving straight through for two or three days is something very few people actually do, and most of them probably shouldn't, so there's a point after which added battery capacity/range isn't really necessary/useful if suitable charging is around.
    Walter
     
  3. Panu

    Panu Member

    Joined:
    Jan 9, 2015
    Messages:
    280
    Location:
    Uusimaa, Finland
    One important area for improvement is battery degradation. In current batteries that will happen for sure and eventually the battery will need to be replaced. Basicly all improvements that could be done are (still) related to battery.
     
  4. Zythryn

    Zythryn MS 70D, MX 90D

    Joined:
    Mar 18, 2009
    Messages:
    1,661
    Location:
    Minnesota
    I agree, however, that really doesn't address the question of where efficiency can be improved.

    As noted, battery chemistry is one area.

    Vehicle weight is another. IMO, the Tesla Model S is the best car in the world. It is not, however, the most efficient.
    This is the biggest reason I am looking forward to the Model S.

    One area I think would be the biggest area of efficiency improvement would be fully automated streets.
    Once all cars are automated, or all cars along certain routes are automated, the system has the potential for huge efficiency gains.

    Imagine driving on city streets and never needing to stop? Cars "talk" to each other as they approach the intersections, allowing both approaching cars to either slow, or quicken slightly so neither needs to stop.

    Now, this is a very long way off, however, IMO it will lead to huge efficiency gains.
     
  5. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

    Joined:
    Jul 12, 2012
    Messages:
    4,503
    Location:
    Maine
    Reliability of the vehicles. Problems noted:
    - Nissan Leaf: battery
    - Volt: bearings, charge port door, climate control, (and some other stuff not necessarily just a PEV thing, from personal experience), some batteries (some people with early Volts have had reports of battery issues, but it's not a significant issue).
    - Model S: everything
    - BMW i3: on-board charger

    I think the different issues encountered by different manufacturers make it clear that longer-term the reliability should be excellent, but they're still learning.

    Also, power electronics: they're still pretty expensive and I think a more likely point of failure than the battery (which will tend to degrade rather than fail).

    - - - Updated - - -

    Oh yeah, I can imagine seeing the sign: "All-Way Yield", and having many, many more rotaries.
     
  6. yobigd20

    yobigd20 Well-Known Member

    Joined:
    Oct 28, 2012
    Messages:
    5,793
    Location:
    Skaneateles, NY
    Maybe they could switch to a multi-gear transmission to be even more efficient.
     
  7. Saghost

    Saghost Active Member

    Joined:
    Oct 9, 2013
    Messages:
    3,038
    Location:
    Delaware
    #7 Saghost, Jan 23, 2015
    Last edited: Jan 23, 2015
    TANSTAAFL. :)

    In this case, the multigear transmission allows the motor to operate in a more efficient range for more of the car's operating speeds in exchange for more mass to drag along and more friction losses at all speeds.

    In some cases that trade-off may be worthwhile, in others it isn't. By and large, electric motors are efficient enough that it hasn't been worth the weight and cost (and gear train efficiency loss) to install a shifting transmission in an BEV.
    Walter
     
  8. rabar10

    rabar10 FFE until Model 3

    Joined:
    Dec 3, 2010
    Messages:
    1,333
    Location:
    Indianapolis, IN
    </super-dry sarcasm> for anyone who didn't catch it ;-)
     
  9. emir-t

    emir-t Member

    Joined:
    Oct 28, 2013
    Messages:
    200
    Location:
    Istanbul
    So the bigger the battery, quicker you get the reasonably needed range. So if we could get (and I know I'm shooting far) a 120kWh battery pack with the Model 3, we could spend time at supercharger stations as much as we do at gas stations now. However Tesla probably is focusing on tighter and lighter batteries for future cars.

    Toughest part on making people go electric despite them being able to clearly see electric is a far better technology when it comes to both efficiency and performance is convincing them that charging won't be a hassle. Now, I know that it is supposed to charge at night and you wake up to a "full tank" etc. but in countries where vast majority of the population lives in apartment complexes, that becomes very difficult to do so. Most people don't have garages and park on the streets. You'd need a whole structural change where municipalities start putting outlets everywhere on the streets.

    Or be able to get like 100-200km range in 5-10 minutes, put superchargers everywhere and solve the issue of road trips as well.

    Don't get me wrong I'm all in for the status quo as well put people feel constrained when they 'have to' spend 20-40 minutes at that exact point because there's a supercharger there. The inability to be spontaneous is what makes them anxious about EVs. This is partly due to lack of infrastructure too it is not all on the technology.
     
  10. shawk

    shawk Member

    Joined:
    Jan 1, 2014
    Messages:
    15
    Location:
    NYC
    Reducing aerodynamic drag may be the best bet. Removing the outside rear view mirrors should lower the drag a lot. Removing the front license plate should also help.
     
  11. bxr140

    bxr140 Member

    Joined:
    Nov 18, 2014
    Messages:
    615
    Location:
    Bay Area
    Yup. That is by far the most important thing to improve.
     
  12. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

    Joined:
    Jul 12, 2012
    Messages:
    4,503
    Location:
    Maine
    #12 ItsNotAboutTheMoney, Jan 24, 2015
    Last edited: Jan 24, 2015
    Yes, if you could charge batteries as fast as you can fill gasoline tanks, the Leaf would sell a lot better and utilities would be installing a gazillion public chargers themselves.

    As for access to charging, I refer to the general approach to home charging as "charge it where you park it". Obvi8usly people who can control their parking spots (driveways) can get access now, otherwise they're relying on others to allow them to get access.

    The next group are people in rented accomodation and multi-unit dwellings with off-street parking. These need market forces to make their landlords and management want to install chargeing points. I think that there's more than enough market in homeowners to get to the point that forces a shift in attitude.

    The final group are people who park on the street. This will need municipal and utility support systematically to install facilities street by street.

    Getting people to understand the ease of plugging in v refueling may be a challenge, but I don't think it's a big one, and I think long range BEV makes it easier because of the reduction of range anxiety and the obvious reduction in the number of days with driving in range.
     
  13. mbender

    mbender Member

    Joined:
    Feb 6, 2013
    Messages:
    14
    Location:
    United States
    #13 mbender, Jan 29, 2015
    Last edited: Jan 29, 2015
    This brings up a probably-silly idea that came to me... But if reducing drag could increase efficiency that much, might it be possible to have the front of the car "transform itself" (as in the toys and the film), say at higher or highway speeds, into a shape that substantially reduces drag compared to the default or "stationary" shape of the front end? Say like something with more of a point, and sharply but smoothly sloping and cone-like 'sides'? It could slowly retract itself as the car slowed down, and quickly retract itself (via collision-avoidance software) -- in addition to being collapsible -- in the event of an emergency.

    I was considering starting a new topic on this question but am glad I found this thread first! I wasn't sure:

    1. How much this would improve the Cd(A)
    2. How much a lower CdA would improve range, and
    3. If it would be worth the expense even if it could be done.
    4. And perhaps, how silly it might sound :redface:
    Oh, and I suspect that it could indeed be done, "technologically", but there may very well be regulatory obstacles that would make it a non-starter even if it could be done, was worth it, etc.

    So... silly, or "something?
     
  14. bxr140

    bxr140 Member

    Joined:
    Nov 18, 2014
    Messages:
    615
    Location:
    Bay Area
    Silly? Nah. Its quite clever actually and in limited form already exists with the louvers in the front bumper.

    Larger scale dynamic shapes are a bit impractical mostly because, like adding solar cells to your hood and roof, the complexity and weight would offset the gains. The front of the car is probably also not the best place for such a device--Dangly bits like the wheels and mirrors would likely be the best place to start, then/or cleaning up the flow peeling off the trailing edges.
     
  15. emir-t

    emir-t Member

    Joined:
    Oct 28, 2013
    Messages:
    200
    Location:
    Istanbul
    I started an entire thread for this; Magnitude of drag and weight's effect to range

    Not the transforming part but the number 1 and 2 you mentioned. Nobody seems to know thus far...
     
  16. bwa

    bwa Member

    Joined:
    Dec 8, 2014
    Messages:
    314
    Location:
    Aptos, Ca
    Rear view mirrors should be easy. Either a camera system, or some snake-like optical transmission (mirrors, fiber bundles, optics, etc. that reflect the image thru the car's body). In both cases, the images would come out to the driver on their left and right. Perhaps a heads up display with all sides and rear view displayed: only one hardware part for all heads up display functions. I'm leaning toward a camera system, sharing cameras with driving assistance automation and liability recorders, and sharing the same heads up display used by everything else (nav, status, etc.)
     
  17. Saghost

    Saghost Active Member

    Joined:
    Oct 9, 2013
    Messages:
    3,038
    Location:
    Delaware
    Cameras are definitely the way to go - Honda is busy demonstrating just how clever and helpful they can be, if you've seen on of the recent Hondas with the Lanewatch right rear view camera (currently on several models in addition to the mirror, it replaces the center console image with a wide angle right rear view with distance markers when you turn on the turn signal.)

    Really, I'd like to see a couple cameras there - one looking to the rear to replace the mirror and feed into a birdseye camera system, and on looking to the front side to watch for traffic at stop signs and lights (for second generation autopilot that can pretty much drive itself anywhere.)

    This would also give near perfect coverage as a dash cam/security system, if the feeds are kept live, combined and recorded correctly.
    Walter
     
  18. bwa

    bwa Member

    Joined:
    Dec 8, 2014
    Messages:
    314
    Location:
    Aptos, Ca
    Re: pointy cars:

    Why wouldn't cars already be made this way? Parking size and maneuverability most likely, and weight. But you see most the trailers going down I5 with their under body wind walls retrofitted, so obviously there's a break even point for more weight to reduce aerodynamic losses, unless all those truck companies are just stupid. A transforming cone is something I thought of to reduce losses when an autonomous carrier was carrying a house-room-height pod (so people can live in their pods and share motive mechanical costs with the other members of the market; obviously high profile vehicles like SUVs lose most their mileage due to aerodynamic losses). But I haven't booked any wind tunnel time at AMES or modeled it.
     
  19. electrocar

    electrocar Member

    Joined:
    Apr 6, 2015
    Messages:
    7
    Location:
    southern CA
    More efficient air conditioners... Go to the "how far can I go" section on the Tesla web site. In the city, at 90 degrees (which is 80% of the weather in southern CA), you loose almost 100 miles in range. One would think there should be more efficiencies there.

    J
     
  20. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,766
    Location:
    Texas
    They are there but they are manual.

    1. Either pre-cool the car if plugged in, or if that's not possible vent the car before driving.

    2. Start with a higher temperature than you would usually have 24/26 C. (don't use range mode). This will actually feel cool compared to the outside.

    3. As the car cools, lower the temperature (leave all the settings on auto and just mess with the temperature). The idea is to never have more than two fan blades turned on.

    4. Keep lowering the temperature as you drive.

    This method works great in Texas where 30-35 is a reasonably cool day.
     

Share This Page