About time to unveil the D and something else

[brianman]

The Model S has always had a standard high definition rearward facing camera

The rearfacing camera has always been standard, but high-def was Tech package (at least originally, but I might have changed since).

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Specifically stated and diagrams show, the car sees 360 degrees.

Has there been any talk of something like Infiniti Around View System?

http://www.infinitiusa.com/now/technology/around-view-monitor.html

The Infiniti Around View System uses 4 vehicle-mounted cameras to create a 360° view of what surrounds the vehicle, displaying it via the in-dash screen.

http://www.infinitiusa.com/infinitihtml/media/culture/images/technology/around-view-monitor/four_cameras.jpg

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I've read this entire thread since it started, and one omission seems to be (unless I missed it) the timescales for the cool new auto-pilot features. I know the lane assist and speed assist are functional, but is anyone concerned, based on track-history, that the uber-cool features, such as self park, self-pickup etc are months, or years away? There wasn't even a demo of any of the parking features, so it sure seems more like vaporware at the moment, and my fear, much like the other vaporware (anything from battery swapping, to using the internal HDD for music storage), is it'll never appear, or take years, and possibly even more hardware once they're really fine-tuned the mechanics of it.

FWIW, Elon stated quite explicitly that they have the hardware needed for these and related features to be fully supported going forward. As such, if he's wrong then owners will have a pretty strong argument that any additional sensors should be no-cost retrofits.

 

[hans]

This brings up a question I have and didn't see it covered yet ... Is the regen going to be coming from the front drive as well on the D models? This could possibly be an excellent means of assisting the braking on ice as opposed to having the TC kick in on the rear wheels only during regen on slippery surfaces.

Regen comes from the brakes, not from the drive so it shouldn't matter how many drive units are in the car. I believe that only the front brakes have regen on them in all models but I could be wrong.

The dual drive units should help for controlling traction on ice by shifting power between front and back wheels based on the traction control sensors.

 

[dhanson865]

Regen comes from the brakes, not from the drive so it shouldn't matter how many drive units are in the car. I believe that only the front brakes have regen on them in all models but I could be wrong.

The dual drive units should help for controlling traction on ice by shifting power between front and back wheels based on the traction control sensors.

regen comes from the electric motor not the friction braking system so any single drive model S has been regenerating with rear wheels only and it takes a model D to allow regen on the front wheels.

Here is a post Tesla made about the roadster but the same tech concepts apply to any hybrid or EV.

The Magic of Tesla Roadster Regenerative Braking | Blog | Tesla Motors

Due to the simplicity of the AC induction motor’s single moving part, the Tesla Roadster does not experience the engine compression braking of a traditional internal combustion engine (ICE). Instead, the advanced algorithms in the motor controller give it complete control of the motor torque for both driving and regenerative braking. A torque command is derived from the position of the throttle pedal. The motor controller converts this torque command into the appropriate 3-phase voltage and current waveforms to produce the commanded torque in the motor in the most efficient way. The torque command can be positive or negative. When the torque serves to slow the vehicle then energy is returned to the battery and presto - we have regenerative braking!

I should also note that the motor and controller can deliver the torque command at any operating speed, including 0 mph. This means that we can regen the car to a complete stop. But as a practical matter, the kinetic energy of a slowly moving car is low enough that very little energy is put back into the battery as the car comes to a stop. In fact, the last little bit of slowing the vehicle down generates such a small amount of energy that it does not even cover the fixed losses in the inverter and motor.

note the friction braking system is there as a safety backup and to allow the car to brake without putting energy into the battery when it is full or overheated. Regen braking never involves the friction braking system.

 

[TimV]

Regen comes from the brakes, not from the drive so it shouldn't matter how many drive units are in the car. I believe that only the front brakes have regen on them in all models but I could be wrong.

The dual drive units should help for controlling traction on ice by shifting power between front and back wheels based on the traction control sensors.

Actually, you are wrong. The regen energy comes from the motors. They act as generators when the car is decelerating. That's why the dual drive is more efficient. It can recover energy from both axles, not just the rear.

 

[hans]

regen comes from the electric motor not the friction braking system so any single drive model S has been regenerating with rear wheels only and it takes a model D to allow regen on the front wheels.

I don't think that is true. Regen comes from the electromagnetic brakes. That's why you get regen when coasting downhill with no power from the electric motor.

 

[Yggdrasill]

Are you under the impression that what was presented on Thursday is the final iteration? If 16 feet isn't enough, then Tesla will change it when the situation calls for it.

It doesn't have to be the final iteration for there to be an issue. Cars are being shipped now with the autopilot hardware, that is supposedly going to have on-ramp to off-ramp capability within a year. Without rearward facing sensor capabilities other than those described in the autopilot presentation, on-ramp to off-ramp is impossible without potentially leading to extremely dangerous situations.

And Tesla needs to be extremely clear on the limitations of the the lane change capability through the turn signal, or people will probably die. It needs to be emphatically explained in detail that it is not possible use the lane change feature without using ones mirrors.

Since you think you know better what Tesla should be doing at this phase of the autopilot development program, perhaps you should apply for a job?

Nah, I won't. Too long a commute from Norway. But I am a senior project engineer at an aerospace company, so I certainly could apply for a job.

 

[brianman]

Regen comes from the brakes, not from the drive so it shouldn't matter how many drive units are in the car. I believe that only the front brakes have regen on them in all models but I could be wrong.

The dual drive units should help for controlling traction on ice by shifting power between front and back wheels based on the traction control sensors.

My understanding disagrees with the underlined portion.

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Also here:

Regen comes from the electromagnetic brakes. That's why you get regen when coasting downhill with no power from the electric motor.

 

[hans]

My understanding disagrees with the underlined portion.

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Also here:

HowStuffWorks

 

[Saghost]

I don't think that is true. Regen comes from the electromagnetic brakes. That's why you get regen when coasting downhill with no power from the electric motor.

We don't fully understand what the electromechanical brakes Elon announced for the D series are - but the legacy model S doesn't have them, and neither does my Volt. Yet both those cars do regenerative braking - which is the drive motor acting as a generator, converting motion into electricity.
Walter

 

[voidptr]

I don't think that is true. Regen comes from the electromagnetic brakes. That's why you get regen when coasting downhill with no power from the electric motor.

Sorry, everyone else is right. Regen is done by adjusting the current on the motor, causing it to turn into a generator.

Induction motor - Wikipedia, the free encyclopedia
Induction generator - Wikipedia, the free encyclopedia

 

[Yggdrasill]

HowStuffWorks

As it says in the article. Regenerative braking works by setting "the vehicle's electric motor into reverse mode". The Model S (non-"D") has it's motor on the rear axle, so it regeneratively brakes with the rear wheels.

This is a fact well known in the Tesla community.

 

[hans]

We don't fully understand what the electromechanical brakes Elon announced for the D series are - but the legacy model S doesn't have them, and neither does my Volt. Yet both those cars do regenerative braking - which is the drive motor acting as a generator, converting motion into electricity.
Walter

Ok. So there are two types of regen then. One uses electromechanical brakes and the other runs the drive motors in reverse. The non D uses the drive motors in reverse method and the D uses the electromechanical braking method. Do I have that right?

 

[livingunique]

If you have legitimate questions, why don't you call or email the company? Pontificating about it on an internet forum seems silly.

Or just buy a Jump to Conclusions mat and have a blast with your friends.

Office Space - Jump to Conclusions - YouTube

 

[gavine]

My DS told me that the motor spin backwards during regen. I didn't have the heart to correct him. In retrospect, I shouad have so he stops spread false info. I guess there's not much harm in him telling that theory.

 

[brianman]

HowStuffWorks

Ok, let's assume that article doesn't suck. I only skimmed briefly but they say regen is motor-tied:

Regenerative Braking Circuits

Regenerative braking is used in vehicles that make use of electric motors, primarily fully electric vehicles and hybrid electric vehicles. One of the more interesting properties of an electric motor is that, when it's run in one direction, it converts electrical energy into mechanical energy that can be used to perform work (such as turning the wheels of a car), but when the motor is run in the opposite direction, a properly designed motor becomes an electric generator, converting mechanical energy into electrical energy. This electrical energy can then be fed into a charging system for the car's batteries.

 

[Saghost]

Ok. So there are two types of regen then. One uses electromechanical brakes and the other runs the drive motors in reverse. The non D uses the drive motors in reverse method and the D uses the electromechanical braking method. Do I have that right?

I don't think so - I have seen nothing to suggest the electromechanical brakes return any energy to the battery - but since I don't know how the electromechanical brakes work, it is theoretically possible until we learn more about them.
Walter

 

[brianman]

My DS told me that the motor spin backwards during regen. I didn't have the heart to correct him. In retrospect, I shouad have so he stops spread false info. I guess there's not much harm in him telling that theory.

Like hans's posts, this post confuses me.

 

[Yggdrasill]

Ok. So there are two types of regen then. One uses electromechanical brakes and the other runs the drive motors in reverse. The non D uses the drive motors in reverse method and the D uses the electromechanical braking method. Do I have that right?

The electromechanical brakes are fairly conventional friction brakes. But they are activated electrically instead of hydraulically or the like. Friction brakes can not do regenerative braking.

 

[dhanson865]

Regen comes from the electromagnetic brakes.

There is no such physical part on a car called "electromagnetic brakes". The electric motor does the regenerative braking with the help of any gearing that ties it to the wheels (transmission, planetary gear set, drive shaft, etcetera).

I'm trying to be nice about this but you aren't even comprehending the article you linked to on "how stuff works"

 

[hans]

If you have legitimate questions, why don't you call or email the company? Pontificating about it on an internet forum seems silly.

Or just buy a Jump to Conclusions mat and have a blast with your friends.

Office Space - Jump to Conclusions - YouTube

Not sure if this was directed at me but I was certainly not trying to pontificate. I simply misunderstood how the regen works on the model S and I thought it was using the same electromechanical system I've seen on other cars (and perhaps even on the D). I apologize if I added to the confusion rather than clearing it up.