BMW Efficient Dynamics: brake energy recovery

[Christophe]

Correct me if I say bullshit, but it seems to me that the% elongation of modern belts is lower than that of chains ... the belt is also much better in terms of friction.

ps: on my VFR, I have even better: a cascade of pinions, this is what is used on industrial engines (20h of lifespan) but since 000 (I believe) they have put a chain on the new model .... pfff

[jean63]

Correct me if I say bullshit, but it seems to me that the% elongation of modern belts is lower than that of chains ... the belt is also much better in terms of friction.

ps: on my VFR, I have even better: a cascade of pinions, this is what is used on industrial engines (20h of lifespan) but since 000 (I believe) they have put a chain on the new model .... pfff

What I know is that the timing belt is a sword of Damocles on the head of each owner of a motor vehicle, because from one vehicle to another and from one brand to another there there is no consistent life ... it can range from 60 km to 000 km and even more (I'm not aware of the latest models).

What I also know is that at Mercedes, they never gave up the chain; I do not think they are more worthless than the others when you know the reliability of this brand. There is another brand that I forgot.

The problem of belt failure other than the distri which is very serious for the engine (valve stems bent at least), that which drives the steering assistance pump can be dangerous for safety because we suddenly find ourselves without assistance in the direction.

I know someone who almost fell into a ravine in Corsica following the rupture of this belt. In my opinion there must be accidents related to this rupture.

On older vehicles, this kind of boredom only involved the water pump and the alternator, so no problem for passenger safety: risk of engine overheating and battery charge stop.

Long live progress.

[Flytox]

Hello jean63

There is that on my old 504 from 1981 (system "disengageable according to the temperature of the coolant in the radiator", extremely simple on water pump pulley: no electronics).

It is incredible that now on all vehicles the cooling fan is permanently driven.

You mean in summer when it's 30 ° at red lights and the muzzle of the car is very "streamlined" so with a very small grille facing the radiator.

[david adv]

When will a car of this technology which tops out at 120km / h, goes from 0 to 100 in 15s and which consequently, would weigh 600kg and consume 2.5l ?.

I only saw the loremo which goes in this direction. other leads?

[Leo Maximus]

... series ! (end of title)

I discovered that all new bmws were equipped series kinetic energy recovery system under braking via a small system mounted directly on the brakes ...

it can be further optimized by recovering the energy lost during braking. BMW has developed a small system directly integrated into the brake disc to convert the energy released with each braking into electric current. The use of the alternator is then exceptional, and the fuel economy is around 4%.

More: http://www.moteurnature.com/actu/uneact ... ws_id=1420

Along the same lines, as standard, they have a whole equivalent of the Start & Stop (which you have to pay 2000 € at Citroën ... well ok the "base" price of the 2 ranges are not comparable but everything likewise) as well as an on-board computer indicating the best ratio / speed to use to minimize consumption (it's not too early) I largely welcome these 3 initiatives because nothing obliged BMW to fit them as standard!

On the new BMW 118d, the power of the diesel engine increases by 15 kW at once. With 143 hp and a maximum torque of 300 Nm, it now allows acceleration in 8,9 seconds (9,0 seconds).
Regardless of the body variant, the maximum top speed of the new BMW 118d is 210 km / h. Despite the increased dynamism, the average fuel consumption in the test cycle in accordance with European standards is only 4,7 liters per 100 kilometers.

Find out more about the brand's "energy" innovations: http://www.xelopolis.com/Xdossiers/doss ... +2007.html

A few years ago I developed a braking energy recovery system for lighting bikes, see: https://www.econologie.com/forums/un-eclaira ... t2551.html

I had also started to experiment with a braking energy recovery system on my old Renault, the principle consists in operating a second alternator with the lighting of the stop lights and / or when you take your foot off the accelerator, this alternator charges a second battery which is used to preheat the engine in the morning before starting, the aim being to reduce the use of the choke. The second alternator uses only energy recovered and stored in the second battery.

[loop]

Hi Maximus

Great idea, I was wondering how to do this simply
You have part of the answer and I think that with only one alternator (the one fitted as standard) this should also be possible
Why not connect a second battery to the first when braking with your principle
The voltage drop across the alternator, following the additional power call, will force the regulator to compensate for the induction of the rotor, and will see its power increase (braking also resistant)
The additional power can then be sent to the second battery
It remains to be seen what we do with this energy?
H2 doping? Brushless alternator supply?

To meditate

A+

[Leo Maximus]

Hi Maximus

Great idea, I was wondering how to do this simply
You have part of the answer and I think that with only one alternator (the one fitted as standard) this should also be possible
Why not connect a second battery to the first when braking with your principle
The voltage drop across the alternator, following the additional power call, will force the regulator to compensate for the induction of the rotor, and will see its power increase (braking also resistant)
The additional power can then be sent to the second battery
It remains to be seen what we do with this energy?
H2 doping? Brushless alternator supply?

To meditate

A+

Yes it is possible and it was like that at the start, the battery was only charged during the braking and / or deceleration phases. What BMW offers today I used it fifteen years ago. At the time I was writing articles for an electronics magazine (Radio-Plans). The system has evolved and the energy from the second battery was used to preheat the engine before starting via a network of ceramic resistors applied against the crankcase.

[abyssin3]

the average fuel consumption in the test cycle in accordance with European standards is only 4,7 liters per 100 kilometers.

About the official cons, I just saw this site :

the actual consumption of this Lexus is indeed 12 liters per 100 kilometers but the manufacturer indicates a consumption of 8,1 liters (...) the Focus C-Max actually consumes 6,7 liters but the manufacturer mentions 4,9 liters (...) Honda Civic Hybrid: it really consumes 6,6 liters per 100 km instead of the advertised 4,4 liters

[loop]

Bonsoir

Maximus
the alternator originally fitted to the engine, rotates with its engine speed, multiplied by the pulley ratio
To benefit from its current production during braking, this requires using the engine brake
The engine brake dissipates kinetic energy in the form of heat by driving the mechanical assembly formed by the wheels, the universal joints, the differential, the gearbox, the clutch and the rotating part of the engine.
In this case, very little mechanical energy is converted into electricity
I think that for a real efficiency, a secondary alternator must be connected to the gearbox outlet and in this case we can disengage during a deceleration or a descent
The secondary alternator can run without production during normal operation, with a minimum of friction, and generate current when voluntarily energizing the excitation during a descent or deceleration, even if you disengage and start neutral
FYI, I achieve 5 to 10% fuel savings with my 205 D simply by using the inertia of the car
I calculated that roughly 20KW mechanical was required to maintain the car at 90Km / h on flat ground
Impressive power if it had to be generated from an electric motor

A+

[Other]

Hello

the alternator clutch if the battery is flat: there is no risk of it being recharged!

Why do you want to put a clutch on an alternator?
it just adjusts the excitation and it turns lightened just two ball bearings to rotate, negligible

Maintaining many alternators on American cars are 100amperes see 120amperes, but we must not believe that it always flows at full capacity, it does not resist a long period at high flow (Delco Remy) if we turn on all glass defrosting, heated seat, internal heating light, ect barely 80 amps.

It remains to know the energy accumulated in a large battery we do what with, if a slowdown or a descent is not used to accelerate the vehicle I find that the gain not very usable.
What eats energy is brutal and unnecessary acceleration and the braking which transforms all energy into heat

Andre