Interesting bits from the Quick Start guide

[idashark]

#18: Headlight Aiming Control was a surprise. ... this allows the driver to lower the headlight beam manually in three steps so as to not blind oncoming drivers.

I thought this was supposed to be fun car! Where the heck is the fun in that? :twisted:

 

[johnr]

Nissan uses in-wheel TPMS sensors, mounted to the inside of the valve stem. Power is provided via kinetic energy which is why the vehicle needs to be driven to generate a reading. A low reading illuminates a warning light on the dash. Reset the warning light by putting air in your tires and driving your car. The light will go out.

Umm I don't think that's quite right. Take a look at this:
"There are two kinds of TPMS technology–indirect and direct. Indirect TPMS approximates tire pressure indirectly by using data from the vehicle's antilock brake system (ABS). Direct TPMS provides a more accurate calulation of your tire pressure using data gathered directly from a sensor placed inside each tire." "The pressure sensor inside each wheel contains a small battery to power the sensor and transponder. Most are long-life lithium batteries that may last from five to 10 years." "Roll switches in the assemblies turn on the sensors when vehicle speed reaches between seven and 20 mph."
Sources:
http://www.aa1car.com/library/tire_monitors.htm
http://www.drive.subaru.com/Spr05_WhatsInside.htm
http://www.tpmsmadesimple.com/how_tpms_works.php

 

[LEAFguy]

Nissan uses in-wheel TPMS sensors, mounted to the inside of the valve stem. Power is provided via kinetic energy which is why the vehicle needs to be driven to generate a reading. A low reading illuminates a warning light on the dash. Reset the warning light by putting air in your tires and driving your car. The light will go out.

Umm I don't think that's quite right. Take a look at this:
"There are two kinds of TPMS technology–indirect and direct. Indirect TPMS approximates tire pressure indirectly by using data from the vehicle's antilock brake system (ABS). Direct TPMS provides a more accurate calulation of your tire pressure using data gathered directly from a sensor placed inside each tire." "The pressure sensor inside each wheel contains a small battery to power the sensor and transponder. Most are long-life lithium batteries that may last from five to 10 years." "Roll switches in the assemblies turn on the sensors when vehicle speed reaches between seven and 20 mph."
Sources:
http://www.aa1car.com/library/tire_monitors.htm
http://www.drive.subaru.com/Spr05_WhatsInside.htm
http://www.tpmsmadesimple.com/how_tpms_works.php

john - thanks for the links. As Nissan never provided us with the details, my assumption was kinetic energy (like a quartz watch) as it did not work until the vehicle started moving. Very clever, these tpms designers!

 

[mitch672]

I can add that the TPMS sensors do NOT last forever. I had a non-factory system put in on my 2004 Prius, the sensor was "strapped" to a band around the wheel, the strap broke, and well, it sounded like broken marbles when driving at low speed (at high speed it was pinned against the inside of the tire by centrifigal force). a new sensor / band cost me $90, and then you have to have the tire removed to install it. Hopefully Nissans are installed on the air valves. and yes, the reason for the rotation required is so the sensor battery will not be on all the time, that's why they last a long time.

 

[garygid]

Apparently the switches keep the sensor's battery from being used while the car is parked, which is a large percentage of each day. Gives a 1-year battery perhaps 10-years of useful "life", I expect.

 

[Coffee_Slurry]

Sure there is - an object spinning in circles is constantly accelerating.

I look forward to your newsletter.

 

[LakeLeaf]

One of the little surprises is that there is an exclusive XM radio button. Since this is a subscription service which many will opt to not renew, that button will just be wasted. Most radios I've seen have some type of multi-toggle "band" button that will just skip XM when it is disabled.

I've also never seen the flip up Nav display with the CD slot behind it. That's kind of neat (if I've read that page right). Just hope that whatever holds the screen in place is break-proof.

 

[DaveEV]

Sure there is - an object spinning in circles is constantly accelerating.

I look forward to your newsletter.

Seriously - an object spinning in circles is always accelerating towards the center of the circle.

 

[thimel]

Seriously - an object spinning in circles is always accelerating towards the center of the circle.

It is true that the TPMS is always accelerating when the car is moving. However, unless one takes advantage of vibration or changes in speed, I don't think there is any way to turn that into electricity.

 

[TEG]

I've also never seen the flip up Nav display with the CD slot behind it. That's kind of neat (if I've read that page right). Just hope that whatever holds the screen in place is break-proof.

Flip up double-DIN NAV screens are rather common for aftermarket systems.

On the drive tour, I noticed one car had the flip up screen damaged in some way so that it wouldn't go all the way back flush with the dash when you closed it. So the mechanism can be damaged if you abuse it, as I imagine someone did when fussing with it during their drive.

 

[DaveEV]

Seriously - an object spinning in circles is always accelerating towards the center of the circle.

It is true that the TPMS is always accelerating when the car is moving. However, unless one takes advantage of vibration or changes in speed, I don't think there is any way to turn that into electricity.

Acceleration will be 9.8 ft/s * 2 different at the top/bottom of the wheel thanks to gravity if you want to design your energy capture device that way, but it's not required.

 

[Coffee_Slurry]

Sure there is - an object spinning in circles is constantly accelerating.

I look forward to your newsletter.

Seriously - an object spinning in circles is always accelerating towards the center of the circle.

In the same way, I'm sitting right here accelerating toward the center of the Earth.

 

[DaveEV]

In the same way, I'm sitting right here accelerating toward the center of the Earth.

Right, but your change in direction is not big enough to notice.

 

[Jimmydreams]

I've also never seen the flip up Nav display with the CD slot behind it. That's kind of neat (if I've read that page right). Just hope that whatever holds the screen in place is break-proof.

Flip up double-DIN NAV screens are rather common for aftermarket systems.

On the drive tour, I noticed one car had the flip up screen damaged in some way so that it wouldn't go all the way back flush with the dash when you closed it. So the mechanism can be damaged if you abuse it, as I imagine someone did when fussing with it during their drive.

My '05 BMW has the motorized, flip-up nav screen for the CD. I rarely use CD's, but mine has never jammed, broken, or otherwise failed to operate as intended.

 

[garygid]

Geneally the flip up/down screens are not very strong, and should not be used as coffee cup holders, like CD "drawers". n

But, treat them gently and you will probably get good service out of the better designs.

 

[planet4ever]

Seriously - an object spinning in circles is always accelerating towards the center of the circle.

That is quite true. And as every student remembers, F=MA, so the acceleration produces a force. But force is not energy. It has to be exerted through a distance to produce energy, and the distance has to be in the direction the force is being applied. Thus the only way to get energy out of that acceleration is to have something move radially toward the outside of the wheel. A weight near the axle can produce one tiny burst of energy when the wheel starts spinning, but then it is pooped out until the wheel stops. If it is fortunate enough to be at the top of the wheel when the wheel stops it can fall back toward the axle (producing another tiny burst of energy from the gravitational force). Anybody care to calculate how many nanawattseconds you could get out of this?

 

[Nubo]

But force is not energy. It has to be exerted through a distance to produce energy...

Thanks! I was beginning to think they had stopped teaching Physics since I went to school

One other way would be to turn the wheel into some sort of dynamo (http://peterwhitecycles.com/schmidt.asp). But the added cost and complexity of any kinetic system makes it hard to beat the use of small batteries since they easily last through 2 or 3 sets of tires before needing replacement.

 

[johnr]

If a coil of wire is mounted on the rotating wheel and a magnet is mounted on the axle in some way whereby it passed near the coil of wire as the wheel turns, then a small amount of electricity would be generated in the coil of wire. But in a car wheel I can't think of any practical place to put the coil and magnet where they can come close enough to each other. Besides, simply using a long-life lithium battery and a centrifugal switch is likely cheaper for the manufacturer anyway.

 

[planet4ever]

But force is not energy. It has to be exerted through a distance to produce energy...

Thanks! I was beginning to think they had stopped teaching Physics since I went to school

Maybe they did. I learned that about 55 years ago.

 

[Coffee_Slurry]

Man, you guys are no fun.. I was hoping drees would explain more of his tire-mounted power-generation system before you go bringing your old-school "physics" and "math" into it.