Hello Robert,
Maybe I missed a post. What kind of EV truck did you find?
Tom
From: robert rabello [mailto:[EMAIL PROTECTED]
To: biofuel@sustainablelists.org
Sent: Wed, 09 Aug 2006 00:40:40 -0300
Subject: Re: [Biofuel] EV is not dead
----- Original Message -----
From: [EMAIL PROTECTED]
Date: Tuesday, August 8, 2006 7:15 pm
Subject: Re: [Biofuel] EV is not dead
> I have been driving these machines for about 30 years now. If I
> haven'tdone some research and gained some experience, it's been a poor
> investment.
I wish more people thought like you do. The fact that you're driving an EV through Canadian winters is admirable. It doesn't get very cold where I live (Shh! Don't tell anyone!), but an EV truck conversion I drove a few years ago illustrated the viability of electric vehicles in this region. Now that gasoline is selling for $1.16 per liter in my area, an EV is looking more attractive all the time.
> There are always going to be circumstances where you have to brake,
> mechanically or electrically (be it plugging, dynamic or
> regenerative).
> >From the point of view of getting back some electricity or just
> makingheat, it is intuitively appealing to think something
> returned is better than nothing, plus it should reduce brake wear and maintenance. I
> don'tdispute that. My issue is the automatic assumption by many
> that it approaches perpetual motion.
I agree with you. I really like the regen braking in my Camry, though, as it helps me control downhill speed. In a car that weighs over 1 500 kilos, being able to regen is a safety advantage as far as I'm concerned. Now, I've NEVER done brake pads on my Ranger, which is approaching 200 000 km on the odometer, but that's partially because I rely on engine braking going downhill. (That little 2.3 liter Ford can REALLY wind!) I'm VERY gentle on brakes, in general, so your comments concerning driver training ring true.
So with a DC motor in your EV, do you rely exclusively on friction brakes? It's hilly where I live, though not as hilly as Southern California, and I don't think I'd want to drive around in a heavy machine that has to rely exclusively on friction brakes.
> But not all downgrades provide regenerative braking opportunities.
True. This is one advantage of a hybrid, in my view. I've dreamed of employing supplemental hydrogen injection for the ICE and using the "wasted" regen braking opportunities to power an electrolyzer, but this would recover very little energy anyway (as most would be expressed as heat)and likely not worth the expense and mass of the additional equipment.
> In mountain country, it can be different, as the grades can be
> longer and steeper. However, when one is starting out with a full charge,
> regenerative braking doesn't work - there's nowhere for the charging
> current to go, hence no motor braking. Plugging might work in this
> circumstance, but it's just another way of making heat.
Once my Camry batteries are full, the regen shuts off and it uses compression braking exclusively. Watching the onboard computer manage energy in the battery pack is a little like watching a delicate dance. I think, however, that a human being with the capacity to anticipate grades could do a more effective job than an electronic system in managing energy exclusively in response to changes in vehicle speed. That's why I shut the cruise control off in mountainous country.
>
> Still, the real catch is how much energy can we expect to get back
> fromregen in the average use of a mass-production vehicle. My
> stance is that
> if it is less than 8% as a starting point for a vehicle used
> specificallyfor stop and go driving, then it's going to be less
> for a vehicle driven with fewer stops and starts. Given the current state of automotive
> technology, there are many places we should focus our energies before
> regen. Reduced weight, reduced drag, more efficient drive trains
> (e.g.,get rid of old-style torque converters). Driver education,
> including the importance of tire inflation, tune-ups, slowing down, planning trips,
> trip-chaining and how to drive for fuel economy.
>
Can I hear an "AMEN"?
> Actually, I remember one of the early production EVs implemented
> regenerative braking, not for the energy capture, but to mimic the
> feel of ICE braking, so drivers new to EVs would feel more comfortable
> with the initial driving experience.
That's what my Camry does too. It's very easy to drive that car in a conventional manner, but I think that's what Toyota set out to do when their engineers first put pencil to paper.
robert
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