Continuous integration with the Siemens VDO eCorner ...

[Philippe Schutt]

Well, I thought the wheels should be as light as possible, in terms of comfort and grip.

[I Citro]

Ooh there, the subject goes in all directions ...

To answer Philippe, Yes the first problem is that of the UNSUSPENDED MASSES (the wheels) which must be as light as possible to have the least inertia and "read" the road well, As the safir reads a microssillon. For this reason, the diameter of the wheels was reduced in the 70s, as vehicles became faster. Then the progress of the suspensions made it possible to increase the diameters of the wheels and the width of the tires to improve comfort and grip. Today we reduce the height of the tire blanks (low size) to increase the space available for the brake discs, to the detriment of comfort. The shock absorbers have therefore become very efficient and able to manage large masses as evidenced by large sports 4x4 (Porsche ...).

For redundancy electrical circuits, our modern cars already have "by wire" controls, therefore not mechanical. I am thinking in particular of the accelerator cable, the handbrake ...
These electrical controls are mutiplexed (encoded and sent over the vehicle network). it is the multiplexing which poses the most problem today. It is rumored that the problem of RENAULT (speed regulators which "block") would come from the lack of redundancy. Unlike other brands which would have at least doubled or tripled their network ...

Finally in the press release from SIEMENS - VDO (truncated by the new obs), hybrid vehicles are mentioned as being a stage in the evolution of vehicles and the e-corner concept a means of supporting this evolution in performance. 50% currently, 85% hybrid, and up to 96% electric with the e-corner.

[Targol]

Ooh there, the subject goes in all directions ...

It is not false, but the subject being vast, it is not very surprising ...

To answer Philippe, Yes the first problem is that of the UNSUSPENDED MASSES (the wheels) which must be as light as possible to have the least inertia and "read" the road well, As the safir reads a microssillon. For this reason, the diameter of the wheels was reduced in the 70s, as vehicles became faster. Then the progress of the suspensions made it possible to increase the diameters of the wheels and the width of the tires to improve comfort and grip. Today we reduce the height of the tire blanks (low size) to increase the space available for the brake discs, to the detriment of comfort. The shock absorbers have therefore become very efficient and able to manage large masses as evidenced by large sports 4x4 (Porsche ...).

To complete this excellent analysis, I would add that the wheels themselves remain light in this project. The device placed in the rim is fixed. So the moving part remains more or less equivalent to a current rim.

For redundancy electrical circuits, our modern cars already have "by wire" controls, therefore not mechanical. I am thinking in particular of the accelerator cable, the handbrake ...
These electrical controls are mutiplexed (encoded and sent over the vehicle network). it is the multiplexing which poses the most problem today. It is rumored that the problem of RENAULT (speed regulators which "block") would come from the lack of redundancy. Unlike other brands which would have at least doubled or tripled their network ...

FYI, on the A380 too, the data is multiplied. But, to have worked precisely on this part, each cable is described, each frame circulating on the cables, each data contained in a frame, and finally, each bit of data. Multiplexing has been studied thoroughly and the redundancy of circuits means that a given computer will receive the same information from 5 or 6 different sources, which makes it possible to quickly detect a defective sensor or cable. Precaution that Renault did not take from what you seem to say ... which only confirms my suspicions ...

PS: If it interests some of you that I make a slightly more complete subject on the particularities of the avionics of the 380 (without going into too much detail, I still signed a confidentiality clause), do it know me by MP.

[Obelix]

Hello,

The subject is not new ... to say the least!
I remember seeing in the 1970s the vehicle of the JARRET brothers who adopted this principle.
They had built AND MARKETED an electric tricycle that served as a golf car.
I think we can still find traces of it on the Web!

Obelix

[Woodcutter]

[...]

To answer Philippe, Yes the first problem is that of the UNSUSPENDED MASSES (the wheels) which must be as light as possible to have the least inertia and "read" the road well, As the safir reads a microssillon. For this reason, the diameter of the wheels was reduced in the 70s, as vehicles became faster. Then the progress of the suspensions made it possible to increase the diameters of the wheels and the width of the tires to improve comfort and grip. Today we reduce the height of the tire blanks (low size) to increase the space available for the brake discs, to the detriment of comfort. The shock absorbers have therefore become very efficient and able to manage large masses as evidenced by large sports 4x4 (Porsche ...).

To complete this excellent analysis, I would add that the wheels themselves remain light in this project. The device placed in the rim is fixed. So the moving part remains more or less equivalent to a current rim. [...]

Sorry Targol, but when we talk about mobile part, it is as Citroen says, unsprung masses, that is to say which have mobility relative to the chassis, which is suspended.
On a classic car, that's all that is at the end of the suspension arms. In this case, it's a little more complicated since Siemens also wants to turn the suspension arms ...
But we can clearly see on the diagram that there is still an important set directly subject to the irregularities of the ground: the tire-rim assembly, the engine then the braking system.

[Targol]

Indeed, Lumberjack, compared to a standard car where the "mobile" elements in relation to the chassis are the wheel (as a whole) and the brake; here we also have the engine, steering and some suspension elements.

Mea maxima culpa

[Philippe Schutt]

in fact, we feel + or- the irregularities of the road as a function of the suspended mass / unsprung mass ratio. large 4x4s have an enormous suspended mass, hence the comfort, which is still very relative, compared to a car designed for comfort, like a C6 for example.
transferring all these active elements into the wheel reduces the suspended masses AND increases the unsprung masses. The effect is double, what am I saying squared!
The price will also be increased by the multiplication of engines. Also, I think that for "normal" cars we will be satisfied with a single central motor per running gear, and conventional steering, but with electric assistance.

[I Citro]

Indeed, Lumberjack, compared to a standard car where the "mobile" elements in relation to the chassis are the wheel (as a whole) and the brake; here we also have the engine, steering and some suspension elements.

Mea maxima culpa

Bucheron intervened before me

I think you were reasoning in terms of rotating masses. in fact, in the motor-wheel assembly, the wheel remains the only rotating element, the hub is fixed. It is the "crown" of the motor which acts as the rotor. If the rotating masses are "contained", the gyroscopic effect too. which limits the energy required to keep the wheel in contact with the ground, but also the energy required to steer the wheel at high speed.

From this point of view, the electric steering is very interesting, because at high speed the differentiated management of the rotational speeds of each wheel makes it possible to turn without using the electric steering. This too is optimization and energy saved ...

To answer philippe the choice of a central engine is certainly economical but greedy in losses of output. These losses are estimated between 15 and 30% (differential, cardans ...)
Finally, the comfort of the C6 comes from the technology used. The hydropneumatic combines a high reactivity (nitrogen compressed to several tens of bars) of a gas which does not heat up and keeps the same hysteresis whatever the load, the frequency and the intensity of the movements to be damped.
This technology has been used under license by Mercedes, Rolls Royce ... other manufacturers opt for pneumatic piloted suspensions with comparable performance. I had this on a saffron ... so comfortable that I fell asleep at the wheel.

[Woodcutter]

[...]To answer philippe the choice of a central engine is certainly economical but greedy in losses of output. These losses are estimated between 15 and 30% (differential, cardans ...) [...]

Very interesting this point that you mention!
Could you estimate the energy losses existing between two configurations:
- two small motors linked to the wheels by universal joints (no problems with unsprung masses),
- two wheel motors (less energy loss)

[Philippe Schutt]

aaah. I understand the reason for this research.