Right - read that. The actual J.... spec outlines the gory details of vehicle weight, that tires can be shaved, tire pressure, etc. I'd like to know exactly why the weight difference between 'curb' and 'as tested' and haven't found it yet.evnow said:
I was wondering what you were saying ... got it.AndyH said:
Okay. Just trying to think what might account for the small difference in density. Perhaps the Volt's thermal management adds just enough weight to bring down the entire pack's specific energy by that 2%. Also, that description of the Leaf's motor still does not equate to "DC Permanent Magnet, brushless." That's a very different animal.AndyH said:
Here's a copy of the 1999 J1634 test procedure: [edit...SAE docs automatically expire after 5 years - this doc is legally dead. But it's very close to the last few generations of J1634 and is likely to be very close to the current version. /edit]AndyH said:
Agreed. Looks like there's still plenty for the EPA to learn about EVs.Smidge204 said:
Not to kill your backstory but it seems overly revisionist. In the context of how easy it would be for the EPA to measure the kWh used in charging the Leaf, I wrote: "J1634 requires that the car be run through test cycles until the traction battery voltage falls below the minimum specified by the manufacturer or the car can no longer meet the speed requirements of the test. There isn't any extrapolation. Run till death." You replied to this as follows:Smidge204 said:
Not so. There were many other things said.SanDust said:
The EPA uses Equivalent Test Weight which is based on the curb weight of the vehicle plus the carrying capacity of the vehicle, otherwise known as Loaded Vehicle Weight. http://edocket.access.gpo.gov/cfr_2008/julqtr/pdf/40cfr86.129-00.pdfSmidge204 said:
I've tried to explain this to you several times. Think about it. If you're trying to determine how many kWh you're putting into the battery it doesn't matter what the kWh/100 mile figure is. The EPA drains the battery. Then it charges the battery and measures how much power has delivered from the wall. It's just simple counting and it's all that matters. The range and the kWh/100 miles only comes into play because you're trying to find how many kWh are in one charge.evnow said:
Yes - the test was 'run until empty' - not the short form. Yes - the EPA knows how to measure how much energy it takes to recharge the pack. You're in fine shape so far.SanDust said:
So the EPA got over 100 miles on a charge?AndyH said:
It is not that you have failed to explain - you have failed to understand. See Andy's post above too.SanDust said:
Yes. Here are the unadjusted figures EPA got, that I posted.DarkStar said:
Short answer: yes, it does simulate those effects. My only question is if the dynamometer the EPA uses for the testing is a driven or passive type... though it may not come into play if they just drive it until dead. A driven type would permit regenerative braking whereas a passive type would only absorb and dissipate energy put out by the wheels.evnow said:
The 'how to conduct a test' document explains in gory details. Everything is modeled and verified with real-world driving to validate the model. They can adjust the model to simulate wind and hills, but I don't know that they do.evnow said:
The evaluation process includes input from the manufacturer and the Government agency. Here are the numbers Nissan reported to the EPA in their application - Normal and Eco mode:DarkStar said:
Part of the test setup is to run the dyno for 15 minutes to warm it up before strapping the car on - that sounds active to me. (This Doc - page 9 paragraph 6.1.4) The LA4/UDDS and US06 include stops so there's opportunity for regen - and range does improve in ECO mode...Smidge204 said:
Interesting that Eco mode seems to have very little impact on range in that test. +1.8% City and +2.3% highway? Meh. I really want to believe there is something being missed that makes ECO mode more worthwhile...AndyH said:
I have NOT spent time reading the referenced info ... but ... is it a simulation or a real drive with "feet-on-the-peddles" ? If simulation ... that would explain the poor "improvements" gained from ECO.Smidge204 said:
Eco mode is really just a drivers aid. A well trained driver should be able to achieve Eco results in regular drive mode.Smidge204 said:
It appears that in addition to throttling the HVAC the regen rate increases in ECO mode. Hard to do that from the accelerator pedal regardless of driver experience.drees said:
Right - but I believe you can get the same effect by lightly pressing the brake pedal as the brake pedal is essentially a dummy pedal which blends regen/friction brakes depending on operating conditions - like the Prius.AndyH said:It appears that in addition to throttling the HVAC the regen rate increases in ECO mode. Hard to do that from the accelerator pedal regardless of driver experience.
I don't know. The Leaf service manual shows a standard mechanical connection between the pedal and master cylinder. It also shows the computerized mixing of regen and friction (with both regen and power brake boost adjusting on the fly with inputs from ABS and traction control). On paper braking seems like a fluid mix. I look forward to feeling it 'for real' to see if that brake spot exists.drees said:Right - but I believe you can get the same effect by lightly pressing the brake pedal as the brake pedal is essentially a dummy pedal which blends regen/friction brakes depending on operating conditions - like the Prius.AndyH said:It appears that in addition to throttling the HVAC the regen rate increases in ECO mode. Hard to do that from the accelerator pedal regardless of driver experience.
