lancpudn:
stu675:
lancpudn:
It would feel weird getting behind the wheel of a car with no brake pedal though. 
fleetnews.co.uk/news/manufa ā¦ for-brakes
Iām sure the regenerative brakes will still be controlled by a brake pedal.
It makes you wonder how it would work if you set out with a fully charged traction battery pack though! If the battery pack is 100% full then there will be nowhere to store that regenerative energy, My MG ZS ev when fully charged wont regenerate any energy back into the pack until itās used up around 4-5%. Itās caught me out a few times as I very rarely charge it to 100%, The regenerative braking doesnāt work & Iāve had to use the brake pedal at the last minute 
The batteries couldnāt take the required level of charge over that short time scale regardless.
Serious regenerative braking is dependent on super capacitor provision not the batteries.
Carryfast:
lancpudn:
stu675:
lancpudn:
It would feel weird getting behind the wheel of a car with no brake pedal though. fleetnews.co.uk/news/manufa ā¦ for-brakes
Iām sure the regenerative brakes will still be controlled by a brake pedal.
It makes you wonder how it would work if you set out with a fully charged traction battery pack though! If the battery pack is 100% full then there will be nowhere to store that regenerative energy, My MG ZS ev when fully charged wont regenerate any energy back into the pack until itās used up around 4-5%. Itās caught me out a few times as I very rarely charge it to 100%, The regenerative braking doesnāt work & Iāve had to use the brake pedal at the last minute
The batteries couldnāt take the required level of charge over that short time scale regardless.
Serious regenerative braking is dependent on super capacitor provision not the batteries.
If* the batteries couldnt take the short term energy input from 1g braking, then maybe a capacitor could be used, yes. Then the stored charge fed less quickly into the battery. No problem I can see. Current (sorry!) batteries are not the same as lead acid batteries that need slow charging. Anyway in the event of needing emergency braking of 1g, then if any energy generated is in excess of batterys ability to absorb it, just let it dissipate as heat. Still does not mean friction brakes are required.
Lets use a battery to slowly accelerate a vehicle.
Then, let`s change the gearing and decelerate the vehicle really quickly.
Voila, more energy generated than used!
Where is my Nobel Prize?
Franglais:
Lets use a battery to slowly accelerate a vehicle.
Then, let`s change the gearing and decelerate the vehicle really quickly.
Voila, more energy generated than used!
Where is my Nobel Prize?
Thatās what I said.
So ( probably ) in exactly the same way that accelerating more slowly by short shifting upshifts and light throttle inputs unarguably uses less energy to reach the same terminal velocity.
But batteries wonāt cut it it.
That rate of charge will need the extra weight and expense of loads of super capacitors in addition.
Franglais:
Lets use a battery to slowly accelerate a vehicle.
Then, let`s change the gearing and decelerate the vehicle really quickly.
Voila, more energy generated than used!
Where is my Nobel Prize?
Thatās not what he said.
Put 100 units of energy into a battery from the national grid. Use 20 of those units to slowly accelerate up to 70 mph in 60 secs. Slam on the regen anchors and stop in 100 feet and recover 10 units of energy, or slowly brake over 1000 feet and only recover 9 units.
Iām with Carryfast on this one.
Franglais:
Carryfast:
Serious regenerative braking is dependent on super capacitor provision not the batteries.
If* the batteries couldnt take the short term energy input from 1g braking, then maybe a capacitor could be used, yes. Then the stored charge fed less quickly into the battery. No problem I can see. Current (sorry!) batteries are not the same as lead acid batteries that need slow charging. Anyway in the event of needing emergency braking of 1g, then if any energy generated is in excess of batterys ability to absorb it, just let it dissipate as heat. Still does not mean friction brakes are required.
Itās not āifā super capacitors are already being used with batteries by manufacturers to provide regenerative braking because batteries canāt handle it.
Which then raises the question of retaining multi speed transmissions in EVs to maximise the energy recovery potential in throwing it into first gear to stop from 40 mph +.
Franglais:
Carryfast:
Itās not a regenerative motor itās just switching the circuitry to to turn the motor into a generator.
Have you been reading Donald Trump`s books on engineering?
To be fair Biden would probably order his EV with seperate electric motors to go and electric generators to stop.
stu675:
Franglais:
Lets use a battery to slowly accelerate a vehicle.
Then, let`s change the gearing and decelerate the vehicle really quickly.
Voila, more energy generated than used!
Where is my Nobel Prize?
Thatās not what he said.
Put 100 units of energy into a battery from the national grid. Use 20 of those units to slowly accelerate up to 70 mph in 60 secs. Slam on the regen anchors and stop in 100 feet and recover 10 units of energy, or slowly brake over 1000 feet and only recover 9 units.
Iām with Carryfast on this one.
The opposite is likely true.
To get greater acceleration or deceleration, a greater current is needed. Greater current means more heat losses.
(Remember that heat is lost according to the square of the current)
If you have a perfect system (with level ground, zero electrical resistance, no friction, no air resistance, etc) then the energy recoverable is equal to the energy expended.
The amount of possible energy recovery, is independent of the rate of recovery.
In the real world lower currents (corresponding to slower changes of velocity) are subject to lower heat loss.
Franglais:
stu675:
Franglais:
Lets use a battery to slowly accelerate a vehicle.
Then, let`s change the gearing and decelerate the vehicle really quickly.
Voila, more energy generated than used!
Where is my Nobel Prize?
Thatās not what he said.
Put 100 units of energy into a battery from the national grid. Use 20 of those units to slowly accelerate up to 70 mph in 60 secs. Slam on the regen anchors and stop in 100 feet and recover 10 units of energy, or slowly brake over 1000 feet and only recover 9 units.
Iām with Carryfast on this one.
The opposite is likely true.
To get greater acceleration or deceleration, a greater current is needed. Greater current means more heat losses.
How so when the the principle of regenerative braking is to recover the kinetic energy released by deceleration.
That energy release is proportional to the level of deceleration which in this case means braking as late as possible using as low gear as possible to spin up the generator to generate as much current as possible to put into the batteries.
As opposed to accelerating as slowly as possible to minimise the amount of energy drawn from the batteries.
Bearing in mind that we know that fuel consumption increases to accelerate to a given terminal speed faster.
While braking late and fast fries brakes.
Carryfast:
Franglais:
stu675:
Franglais:
Lets use a battery to slowly accelerate a vehicle.
Then, let`s change the gearing and decelerate the vehicle really quickly.
Voila, more energy generated than used!
Where is my Nobel Prize?
Thatās not what he said.
Put 100 units of energy into a battery from the national grid. Use 20 of those units to slowly accelerate up to 70 mph in 60 secs. Slam on the regen anchors and stop in 100 feet and recover 10 units of energy, or slowly brake over 1000 feet and only recover 9 units.
Iām with Carryfast on this one.
The opposite is likely true.
To get greater acceleration or deceleration, a greater current is needed. Greater current means more heat losses.
How so when the the principle of regenerative braking is to recover the kinetic energy released by deceleration.
That energy release is proportional to the level of deceleration which in this case means braking as late as possible using as low gear as possible to spin up the generator to generate as much current as possible to put into the batteries.
As opposed to accelerating as slowly as possible to minimise the amount of energy drawn from the batteries.
Bearing in mind that we know that fuel consumption increases to accelerate to a given terminal speed faster.
While braking late and fast fries brakes.
The amount of energy is related to the speed and mass of the vehicle.
It is not related to how rapidly that energy is changed.
The rate of energy release is related to the deceleration (the rate of velocity change).
The amount of energy is not related to deceleration.
Decelerating more rapidly will generate higher currents, yes. But for a shorter period. The total amount of energy remains the same.
[Slow down twice as fast, and you`ll be slowing down for half as long.]
Decelerating gently will in fact have lower currents and hence lower thermal losses.
Franglais:
The amount of energy is related to the speed and mass of the vehicle.
It is not related to how rapidly that energy is changed.
The rate of energy release is related to the deceleration (the rate of velocity change).
The amount of energy is not related to deceleration.
Decelerating more rapidly will generate higher currents, yes. But for a shorter period. The total amount of energy remains the same.
[Slow down twice as fast, and you`ll be slowing down for half as long.]
Decelerating gently will in fact have lower currents and hence lower thermal losses.
You can decelerate a 44t truck from 56 mph to zero without putting any energy into the brakes at all if itās done over a long enough time.
While you can fry the brakes of a less than 1,000 kgs race car just because of the time and distance required to decelerate.
Whats that if it isnāt the relative āamountsā of energy put into the brakes doing it in both cases ?.
While the faster you spin a generator ( by throwing it into first gear at 70 mph ? ) the more current it produces it isnāt dependent on torque.Only the acceleration is torque dependent which an electric motor provides in spade loads.
Brake particles to be included in the upcoming Euro 7 standard emission rules. What are they going to do? retro fit every vehicle with a brake dust capture system.
"Ultra-fine particles from brake pad abrasion will for the first time be covered under an EU regulation to curtail vehiclesā contribution to air pollution, a move aimed at reducing the high level of the toxic particles in urban areas.
The upcoming Euro 7 regulation, set to be unveiled in July, will force vehicle manufacturers to reduce the quantity of pollutants, such as nitrogen oxides and sulphur oxides emitted by cars." euractiv.com/section/electr ā¦ ion-rules/
I,m with Juddian on this.I expect my diesel Mondeo to last longer than me.
