TAmes

I know the F10s have this feature, where the alternator is engaged only during coasting and braking. Anyone know if U.S.-spec E60s had this feature? Just curious.

Thanks in advance.

-TA

Dandle

LCI cars do its part of Efficient Dynamics which was introduced on the LCI E60. It does engage more then that and will only start to disengage once the battery is topped up.

TAmes

Thanks for the reply, Dandle. Appreciate it.

v_therussian

Ironically, Dandle is from UK and I think US-spec E60's never came with brake-energy regeneration. If they did, I'd actually consider retro-fitting one of these things, except it won't really make a difference IMHO. The way this brake force regeneration should work is give you extra power on exits out of turns, but I don't think it is really worth the added weight in commercial applications. In racing cars these systems are light enough and efficient enough to give an added edge to the driver, but in production cars still seems pointless. Again, unless it actually is lightweight.

Dandle

I would imagine that it's not just a European thing, the cost of having a car wired different for the American market wouldn't be worth it. ED was rolled out on the LCI cars and the idea isn't to give more power but to make the cars more efficient, although the LCI cars did get a slight power boost. ED also included active aerodynamics(which the E60 already had), low friction fluids and tyres and other things like optimum shift indicator on manual cars. You can tell if the American cars were fitted with it if the LCI cars became more efficient over the pre LCI ones.

Michael-Dallas

You're thinking of the wrong thing. This is BMW's Brake Energy Regeneration: http://www.bmw.com/com/en/insights/t...eneration.html

In that article, "generator" = alternator. It simplies engages the alternator clutch while you are braking or coasting to recharge the battery and disengages the alternator clutch when you are accelerating.

Michael.

v_therussian

Here's an article from bmwblog, that says the 5 Series GT was the first 5er to have BER in US:
http://www.bmwblog.com/2009/05/24/bm...on-technology/

I think this pretty much settles that BER was never used on US-spec E60's.


Maybe I just don't know LCI cars well enough, but to my knowledge there are no brake force regeneration systems on E60's in the U.S. - LCI or not. F10 - yes. Perhaps, someone from US can step in and correct me if I am wrong.

Sorry, I think I misspoke. What I was trying to convey is, the system, where brake force is stored as electric energy is far inferior to a kinetic/mechanical-energy system (aka KERS). In the latter a flywheel is spun during braking, storing the energy recovered from braking in kinetic form. This method allows less energy dissipation, is elegantly simple from engineering standpoint and weighs significantly less than an electric-energy storage system does. IMHO electric system is almost pointless, as any efficiency gains are negated by the added weight. It is more pointless on a non-hybrid car, where the mechanical energy from braking must be converted to electrical energy, stored and then, when called upon, be converted back to kinetic energy and applied.

I believe the system used in BMW's is actually neither and all it does is allow for an occasional disconnect of the alternator, making the engine operation more efficient, but adding zero performance. Any benefits from it - in my mind, at least - are questionable. Although, a "clutched" alternator is the way of the future, I really think its application in current non-hybrid models is a pure marketing move. I seriously doubt it adds any efficiency at all - forget about performance.

There, I think I explained myself a little better this time

In all honesty, I wish someone came up with a retrofit KERS system - it would revolutionize modifying performance cars IMHO. Problem is, this system is not developed to the point where a commercial application is feasible. Or to put it even more accurately, the system that is possible to produce feasibly is not efficient enough to justify its cost to the end user.

Dandle

Seems Brake Regeneration was introduced with efficient dynamics in the US LCI launch like I thought. https://5series.net/information/2008...Release_US.pdf

v_therussian

I stand corrected. Good job

Michael-Dallas

Indeed, you or I may not individually realize the benefits, but think of all the 5-series out on the road as a whole. If BMW can improve fuel economy by even 0.25mpg with Brake Energy Regeneration, then that number becomes a big number if there's 30,000 5-series on the road, just in the U.S.

Brake Energy Regeneration is part of Efficient Dynamics, which is a focus on lowering emissions and increasing fuel economy while not compromising performance.

Michael.