Remember that the early Teslas had a two-speed transmission that proved
to be a disaster. They cured the problems by simply removing the source
of the problem: The transmission.
If you install proper motor cooling and controller cooling, and perhaps
upgrade the motor or controller, then the desire/need for a transmission
naturally goes away.
There is really never a need for a transmission in a well-designed EV.
It adds complexity, cost, and inefficiency.
It is a red flag to investors when a start-up EV company proposes using
a transmission. It shows they have not really done the modeling
correctly, or they have installed a mismatched drive system and are
trying to "fix" it with a transmission.
Bill D.
On 7/21/2014 7:44 AM, brucedp5 via EV wrote:
Bosch sez Gear changes will soon be part of EVs
http://ecomento.com/2014/07/14/prototype-golf-proves-gears-make-electric-cars-go-further/
Prototype Golf proves gears make electric cars go further
July 14, 2014 – Stephen Edelstein
[image
http://cdn.ecomento.com/wp-content/uploads/2014/07/step2-electric-golf.jpg
]
Thanks to their instantaneous torque delivery most electric cars get along
with a single forward gear. BMW, Nissan, and Tesla all employ this strategy,
yet German automotive supplier Schaeffler thinks more is better.
The company entered its STEP2 prototype in the fifth Silvretta E-Rally in
Montafon, Austria, to test a new two-speed transmission that it believes can
improve the efficiency of electric cars.
Schaeffler stripped the internal combustion powertrain from a Volkswagen
Golf, adding a complete electric powertrain and the novel transmission,
which features a low gear for traction and a high gear for higher-speed
cruising.
The company says the STEP2 has already achieved an efficiency improvement of
around six percent over a comparable electric car in simulations and tests.
That’s six percent more energy that can go towards increased range.
Internal combustion-engined cars need a spread of gears to match road speed
with engine speed, but since electric cars produce all of their power no
matter what speed the engine is turning, multiple gears have largely been
viewed as unnecessary.
Schaeffler believes an additional gear will allow the motor to work less
hard to propel the car at a given speed, improving efficiency. It’s like a
riding a bicycle: a gear that works well for sustained speeds might require
more effort from the rider when starting out.
That makes for a tired cyclist, but also a less-efficient electric car. The
harder the motor has to work, the more electricity is required to keep the
car moving.
The STEP2 doesn’t exactly put an abundance of power at the driver’s
disposal. Its output is just 50 kilowatts (67hp) in continuous operation, or
70 kW (93.8hp) at peak.
The Silvretta E-Rally is the perfect place to test this setup. Unlike
conventional road rallies, where the object is to complete a set of stages
in the shortest elapsed time, victory in the E-Rally goes to the team that
finishes with the least amount of energy used.
[© ecomento.com]
http://www.fleetnews.co.uk/news/2014/7/14/gear-changes-will-soon-be-part-of-evs-says-bosch/52966/
Gear changes will soon be part of EVs, says Bosch
14/07/2014
Transmission technology will soon find its place in electric vehicles (EVs),
just as it has in petrol and diesel vehicles, according to Bosch.
Electric motors have no difficulty in running up to 20,000 revolutions per
minute (rpm) – compared to petrol or diesel engines, which usually only run
up to a maximum speed of around 9,000 rpm – and so can run in a single gear,
without the need for a transmission.
To think of transmission and electrification as opposites is a
misconception. Whether you're talking about an electric drive or a petrol or
diesel engine, the right transmission will make any engine more efficient.
As electric vehicles become more popular, motorists are being introduced to
automatic vehicles that do not use traditional transmission.
Most electric vehicles effectively operate in one gear without any need to
change up or down – with reverse and neutral as the only options.
Bosch believes that changing gears will soon be part of the electric
vehicle. High-precision automatic transmissions are essential in hybrid
vehicles to ensure that the combustion engine and electric motor are
synchronised with each another, but such transmissions could also find their
way into pure electric vehicles.
EV sales predictions
Looking at all new vehicle sales worldwide in 2020, Bosch expects at least
6.5 million hybrids, 3 million plug-in hybrids, and 2.5 million all-electric
vehicles, alongside some 100 million petrol and diesel cars.
In 2013, there were 1.5 million hybrids, 90,000 plug-in hybrids, 100,000
all-electric vehicles and over 60 million petrol and diesel cars sold
worldwide.
In 2013, more than half of all new cars and light commercial vehicles sold
had an automatic transmission. In future years, Bosch believes automatic
transmissions will increasingly overtake manual transmissions worldwide.
In terms of the future, the biggest driver for modern transmissions is the
desire to reduce CO2 emissions, according to Bosch.
They are primarily designed with one goal in mind and that is to keep the
engine as close to its optimum operating level as possible.
There are already some very efficient nine-speed transmissions on the
market, and it's only a matter of time before ten-speed designs come along.
[© fleetnews.co.uk]
...
http://gas2.org/2014/07/20/bosch-electric-cars-will-soon-transmissions/
Bosch: Electric Cars Will Soon Have Transmissions
For all EVLN posts use:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/template/NamlServlet.jtp?macro=search_page&node=413529&query=evln&sort=date
http://www.wfxl.com/news/story.aspx?id=1070304
Solar charging an EV is a smart, sound, long-term financial decision
http://www.autoevolution.com/news/tesla-owner-talking-you-through-model-s-battery-degradation-video-83897.html
Tesla Owner Talking You Through Model S Battery Degradation (Video)
http://www.autonews.com/article/20140715/COPY01/307159971/bmw-open-to-sharing-battery-technology-with-rivals
BMW open to sharing battery technology with rivals
...
http://www.telegraph.co.uk/motoring/car-manufacturers/bmw/10968085/BMW-to-spend-billions-buying-Samsung-SDI-Batteries.html
BMW to spend billions buying Samsung SDI Batteries
http://blog.sfgate.com/techchron/2014/07/10/campbell-clean-tech-company-snags-deal-with-volkswagen/
2015 e-Golf owners get a free ChargePoint network membership
...
http://ecomento.com/2014/07/11/chargepoint-and-bosch-chosen-to-power-volkswagen-e-golf-drivers/
ChargePoint and Bosch chosen to power Volkswagen e-Golf drivers
+
EVLN: €21k Europeans have the Zoe EV advantage r:90/130mi
{brucedp.150m.com}
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