42V automotive system. What's the latest?

[jims99]

I know the industry several years ago was picking up steam in designing future vehicles with 42V system.
I recently heard rumors that none of the major car manufacturers are actually doing it soon, and in fact some manufacturers abandoned completely future plans.

Anyone has info?


Jim

 

[evelrod]

Jim, what little info I have read lately mirrors your experience. I would guess that current advancements in fibre optics has slowed or postponed the immediate need for a new electrical setup. Just a guess. Perhaps there is someone here that is actually working on this that can bring us up to date on progress or, lack thereof. I know that the U.S. military is still at 24v and there are no changes on the horizon for them that I can find.

Rod

 

[btrueblood]

I thought one of the major reasons for the shift was to allow for smaller sizes (for a given torque output) for electric drive motors. Since the "death" of the GM electric car, maybe people are having second thoughts?

 

[carnage1]

I have seen a lot of information on 42v systems in conjunction with the new electric power steering setups. All the electric power steering companies (on there websites) are talking a lot more about 42v systems than 12 v systems.

besides making smaller motors 42v allows much smaller diameter wires, less copper and less weight= big$
how soon it is coming I havent heard for certain but it isn't dead yet.

 

[gerhardf]

I think the whole thing won't take up some steam until a major manufacturer comes out with a production line car (probably high end or maybe a specialised vehicle) with a 42V system. With the increasing number of wires and electric actuators in the cars, it is probably only a matter of time. But OTOH with the number of 12V systems and accessories on the market, this time is probably going to be pretty long. And maybe other developments make this all obsolete in the meantime...

 

[jons999]

From what i have heard the whole 42v thing is on the backburner. 42v systems were supposed to reduce the size and weight of vehicle wiring harnesses, however we now have high speed serial communication busses such as CAN and AVC-LAN networks that allow one or two wires to carry the information that previously required an entire wiring harness. With hybrid vehicles the entire powertrain is high voltage and they only require a small 12v battery to powerup the computers, lights, and accesories. The cost to redesign all those systems and accesories for 42v wouldn't yield much of a benefit.

-Jon

 

[optimum]

Until the epa pushes for a 0 idle time regulation, I dont think the oems will spend the money on 42 volt hvac/steering/brakes

 

[crysta1c1ear]

 

[optimum]

I thought exide and johnson had small 36 volters that would package a lot better. What is this that you posted?
Tim

 

[Ron07663]

42 Volts: The View from Today
Paper ID: 2004-21-0094
Author: Thomas Keim, Massachusetts Institute of Technology

This is a good industry status summary printed in Convergence 2004 Proceedings. The article was also reprinted in IEEE Vehicular Technology Society News Vol. 51 No. 4 November 2004.

 

[jims99]

Thomas,

Since most of us have no access to this publication, can you share with us summary of article.

Regards,
Jim

 

[Ron07663]

jIMS99:
I'm not making a commission on this but this article is worth the few bucks it cost to download. The list of references at the end of the article will direct you to even more detailed information.

http://www.sae.org/servlets/productDetail?PROD_TYP=PAPER&PROD_CD=2004-21-0094

It describes the technical hurtles and economic challenges that ultimately quenched the initial industry enthusiasm. Basic component such as switches, relays, connectors and fuses needed re-design. Dual voltage schemes had additional complications. All these were solvable but re-design was expensive. Work-arounds were also found for many power-hungry devices that enabled keeping the 12 V system. According to the article, 42 V is not yet dead, just on life support. There are 2 vehicles in production and 2 more in the works.
Sorry for lack of details here, but I never liked to do book reports in school.