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RogerHScott
Active Member
Took my car out for a short drive in low-single-digit temperatures yesterday, parked for lunch, then drove home. For the duration of the entire trip I had zero regen (despite having warmed the car up before leaving). So, question for all of you single-pedal drivers out there: what do you do under these condition (or, for that matter, when you've just put on a trip charge and have no regen due to that)? Do you ever find yourself taking your foot off the accelerator and wondering why you're hurtling toward the car in front of you? A driving mode that relies on an unreliable deceleration mechanism seems rather dangerous. Wouldn't it be safer to put the regen on the brake pedal and have everyone consistently use traditional two-pedal technique?
"How about startup messages on main screen, customized to level of temp car senses, that explain limitations car is about to impose along with increased consumption and decreased range guidelines."
Excellent idea and soo easy to make happen, if only.....
Excellent idea and soo easy to make happen, if only.....
Acho
Member
Most likely they know the temp. All pressure sensors I worked with have temperature sensor built in for temperature compensation of pressure measurementWould it require rocket science for the TPMS to take the ambient temperature into account? Wait, even if it would...
Wind chills last week were -30F at night but I keep my car garaged. Maybe that's all it takes too avoid it.
Mine has been starting out at a hopeful 10-14F and dropping as I drive and its introduced to reality without 4 walls and a roof.
Personally, I always have the energy display in the IC screen, so I know when the car has no regen. Pretty simple to figure out when the brake is going to be necessary. When regen is that limited, I’m going to have the heat on in the car so I just start driving and between accelerating, decelerating, and cabin heating I usually get a bit of regen back within a few minutes even after an 8-hour cold soak sitting outside at work. If I can, I’ll try to do a couple hard accelerations as well to try to get some heat in the battery. I typically don’t get more than about 20 kW of regen on the power meter most days between Nov 1 and Mar 30, but even that amount is fine for single-pedal driving if you leave space to the car in front and start slowing early.
For me, I would hate to see regen move to the brake pedal. It’s one of the things I love most about the car.
RogerHScott
Active Member
Specifically it being (only) on the "accelerator" pedal, and not just regen in general?
Hitting the brakes also Regens. Car has Bosch iboost which allocates physical and Regen braking.
One pedal is the best. No need for anything else.
Yes, one pedal to rule them all.
I have read descriptions of various other schemes, i.e. Bolt with the paddle, BMW’s method with the brake pedal, but they all seem more complicated. The main complaints I have heard about cars like Prius is the mix of mechanical and electrical braking is hard to get right so the brakes feel odd. My brakes feel just like brakes, and most of the time I don’t need them which I prefer to always using the brake pedal and leaving it up to the software to decide how much braking force should come from the motor and how much from the calipers.
However, never having driven another vehicle with regen, I am open to the idea that a better method exists. I just find it hard to believe.
Would it require rocket science for the TPMS to take the ambient temperature into account? Wait, even if it would...
@Nick B
It knows ambient, but that does not matter. The tire needs a certain PSI in it. The amount of self heating is fairly the same regardless of outside temp. Therefore, the resting/ cold temp is a constant. If it is -20 out, the air in the tire will never reach the temp is was in the fall when you filled the tires, not will the tires reach the required pressure.
They need more air molecules in winter and less in summer. So you need to add/ remove air as the seasons change.
RogerHScott
Active Member
I would estimate that of all of the times I've gotten a low pressure warning in cold weather fewer than 10% of the time was adding air the right answer. The other 90+% of the time simply waiting was the right answer. So, for me, at least, your approximation is wrong 90+% of the time. And I have never intentionally removed air from my tires. Ever.
It's not my approximation, it's pure physics.
Pv=nrT
Original TPMS trigger threshold was 25% underinflated, not a good reference point.
If the tires were filled at 25C (68F), they will be 10% low at -9C (15F). Would you fill your 45 PSI tires if they read 40-41 PSI? I know I would. Although, if you wait for the weather get warmer, they will eventually reinflate...
It gets worse depending on the moisture content of the air, part of the nitrogen fill idea.
