|
Have you ever been to that part of Rome where famous
poets like Keats, Shelley and Byron once lived. Yes, this place
is just about walking distance from another famous landmark of ancient
(and modern Rome, the Trevi Fountain where countless people throw
coins over their shoulders for dreams throw coins over their shoulders
for dreams and wishes to come true.
The area I am talking about has the Spanish steps
in its centre and is quaint in a very romantic kind of a way. And
as I sat on the steps where Keats might have once trod, I could
not help but admire how pristine and well preserved all the ancient
buildings in the area looked. The next thing I noticed was that
all the vehicles passing through that area were EVs, as electric
vehicles are called these days.
On further enquiry I was told that only EVs were
allowed to ply on the cobblestoned streets of the ancient section
of Rome. Well, on my next visit, it would be nice to see the REVA
at the Spanish Steps! The Delhi Administration has a fleet of electric
mini buses plying the capital's streets as early as the late 1980s,
but there has been not much progress since. Even as most major manufacturers
have EV projects well underway and have a number of such vehicles
being sold in niche markets, the future of the automobile is veering
more towards the hybrid (for the medium term) and fuel cell 9for
the long term) way.
The major stumbling block for the EV has been the
on board storage of energy. Recently a limo EV was in the news for
having a top speed of over 300 kmph but it was using the expensive
lithium-ion batteries as power source. It is indeed laudable that
an Indian company in the form of the REVA Electric Car Company (RECC)
embarked on the development of an EV. The REVA is the brainchild
of Chetan Maini, managing director of the REVA Electric Car Company
(RECC). Chetan was interested in alternate energy vehicles right
from his college days at Standford where he was studying for a graduate
degree in mechanical engineering. Prior to taking over as the managing
director of RECC, Chetan worked for five years in the US with General
Motors and Amerigon Inc. As a program manager, he was responsible
for all EV projects in that company. In fact the REVA project saw
light of day with the establishment of Maini Amerigon in establishment
of Maini Amerigon in 1995 as a joint venture between the Maini Group
and AEVT Inc of Irvindale, California. The Maini Group is a well-known
Bangalore-based industrial house engaged in the manufacture of high
precision components and materials handling equipment. Promoted
by a family of auto buffs, it was just a matter of time until the
group got into something automotive. The first prototype was showcased
in 1996 and since then the REVA electric car has undergone continuous
development, rigorous testing and upgradation to reach the production
vehicle of today. The deliveries of the first 10 such vehicles were
made just a few days back. The body of the REVA is made up of a
tubular steel space frame.
Space frame body construction is employed by many
contemporary-design vehicles like the Fiat Multiple and has advantages
of hindrance-free and high interior space, exterior volume ratio,
structural rigidity, besides forming an energy absorbing shell of
great value during crashes. The body framework is light and could
have been still lighter if aluminium alloy were to be used in place
of steel. Even though a number of alloy frame prototypes were made
and have been tested, the advantages of such a weight reduction
does not offset the high cost increase, feels the managing director.
The body panels are of ABS and have the advantage of being able
to absorb high impact without deforming or breaking and at the same
time being very lightweight. The bumpers too are designed to be
energy absorbing both in terms of their shape as well as the materials
used. The complete design work for the REVA car, including 3d-modelling
of all the assemblies, sub-assemblies and all the individual parts,
analysis of the entire chassis, thermo forming tooling work of all
the body, has all been done in house by REVA Design Engineers with
assistance from Parametric Technology Corporation (PTC) whose software,
Pro/E was used, not only for all the design work but also for checking
for interferences, clearances etc as well as the functional simulation
for the entire chassis, REVA Design Engineers were able to do structural,
motion and vibration analysis as well as optimisation of the chassis
under the guidance of PTC Consultants and using PTC software.
The under-bonnet area that normally houses the
engine has space for a spare wheel, the hydraulic fluid reservoir
for the brakes also serving as a crumple zone in the event of a
head-on or frontal crash. The car is a two door hatchback with two
bucket seats from the India (on the couple of prototypes that I
drove) up front, a bench seat roomy enough for two children at the
rear. Behind the rear seat is just space enough to put in a few
thin shopping bags or a couple of briefcases. But the backrest of
the rear bench seat folds over and to behold, there is space enough
for all your shopping, groceries and whatever else you can think
of on the city trips. The integrated power supply and drive system
on the REVA consists of a high torque (70 Nm) 5 KW continuous, 13
KW peak output DC motor which is mounted at the rear axle. The motor
is currently imported but efforts are being made to indigenise it.
A microprocessor based controller controls the delivery of current
to the motor and ensures smooth acceleration and precise speeds
based on the position of the accelerator.
The computerised motor controller too is imported
and is manufactured by the US company Curtis, which is the world
leader in motor controller for electric vehicle applications. Not
only does the motor controller ensure smooth starts and stops but
also helps the car to be driven in any one of three modes forward,
economy and reverse. Apart from these functions the motor controller
also does regenerative braking and recharges the power pack through
the motor when braking. The hydraulic system comes into play only
during emergency braking the motor acts as a generator, drawing
power from the wheels through the transaxle and charges the power
pack through the motor controller.
The motor controller also keeps a thermal check
on both the motor and itself and prevents either of them from overheating.
It also constantly updates the energy management system (EMS) on
its functioning. The intelligent EMS is the hub of all electrical
activity in the REVA.
|
It is again a computerised system that continuously
and actively interfaces with all the electric activity in the REVA.
It is again a computerised system that continuosly and actively
interfaces with all the electric systems in the car, monitors them
and informs the user through a series of telltale lights in the
instrument panel.
It is developed by RECC itself, using proprietary
technology. The main function of the EMS, apart from monitoring
all the electrical systems, is to optimise the flow of energy from
the power pack to maximise driving range. In case of the charge
on the powerpack running low, the EMS limits the drawing of energy
thereby maximising range.It also monitors and controls the process
ensuring an optional charge each time.
It lights up a warning light in case the level
of water in the batteries of the power pack goes down to a minimum.
Filling of distilled water into each cell of the power pack is a
simple operation in the REVA as it has a centralised feeder pipe
at the edge of the charging port where service centre personnel
can centrally fill up all the cells.
The EMS also detects a problem that it cannot rectify,
then a service light lights up in the instrument panel. The service
personnel then have to hook up a portable electronic tool (PET)
to the EMS and using advanced vehicle diagnostics can easily isolate
the problem and rectify it. The PET is basically a PalmTop computer
with Advanced Vehicle Diagnostic software loaded on it.
The power pack of the REVA consists of eight 6-volt
tubular EV lead acid batteries. These batteries were earlier imported
from the UK but are now being manufactured by the company that makes
Exide batteries. Since EV applications require special batteries,
such batteries were not being made in India prior to the REVA and
only because REVV facilitated the transfer of technology can they
be made here.
The batteries can be charged from any 220v 15-amp
power source. A full charge takes about six hours while about 2.5
hrs can charge the power pack to 80 percent capacity. A full charge
takes about 9 units of electricity and is good enough for about
80 km of driving. RECC puts the cost of driving the car at 40 paise
per kilometre.
An on board charger has a built in stabiliser and
transformer for converting AC to DC and ensures optimum current
and voltage during charging. It also features an auto shut-off function
which will shut-off function which will shut off the current once
the batteries are fully charged. Getting behind the wheel feels
the same as any other vehicle till you notice that the clutch pedal
is missing and so is a gear lever. Lowering the parking brake and
switching on the ignition brings you to a knob on which you can
select any of R, N, E, F options. While N is for neutral, R is for
reverse, F is for forward and E is for forward in the economy mode.
If you select E, acceleration as well as top speed will both suffer
in the interest of range. Turn the knob to f, put pedal to metal
and you will be surprised at the initial acceleration which RECCengineers
tell me is good enough to challenge a Maruti 800 till a speed of
about 30 to 40 kmph. With its small size a speed of 60-odd kmph
feels fast even though there is enough regenerative as well as hydraulic
braking to haul you back.
Even though the REVA is a tall looking car, its
centre of gravity is very low as the power pack (the heaviest part
of the car) sits under the seats. Other heavy bits like the motor
are even lower down. The ride is a little bumpy mostly because the
car is shod with Michelin XT 1, low rolling resistance asymmetric
tubeless tyres which have to be inflated to 40 psi. It drives well
on good city surfaces but is raggged on bad surfaces.
RECC engineers are looking at that aspect too and
the production cars should have a better suspension setup. Motor
whine is quite audible too on the early prototypes that I drove
but was somewhat lower on the later ones and I am led to believe
that it will be completely gone on the production cars. There is
nothing else that I can really fault the car for - interiors house
the six-feet plus lanky frame of the RECC managing director with
ease. The wheel arch does cause a little discomfort to the co-driver,
but a little readjustment of the seat should do the trick. Ineterior
fit and finish is still being worked on and should not be too much
of a cause for concern keeping in mind that a good job has been
done on the exteriors.
Low operating costs, a virtually no maintenance
costs, a three year warranty and refuelling from any electric socket.
What more can you ask for? An 80 km range is too little, say some
but then my wife drives a maximum of 15 km to office in the morning
where the car is parked throughout the day. Then another 15 km home
in the evening, stopping at the market to do some shopping, may
be a detour of a max of 10 km. On weekends she might make odd trips
for knickknacks, but if we are together then we normally use my
car. Which makes 80km seem a mighty long distance.
But the stumbling factor is the high initial cost.
At Rs 2.5 lakh, all inclusive, it is a little steep for a car that
has a limited role specially if individuals are buying it. For corporates
though, it works out a lot cheaper as they end up saving by way
of 100 percent depreciation that can be claimed in the first year
itself.
Here the government needs to step in and to give
a boost to EVs, it needs to work out ways and means of giving such
life-friendly vehicles an edge over the others. I wish that the
REVA is a big success as the world needs such non-polluting vehicles.
For cities like Bangalore where it is first being launched, it is
ideal.
The company is setting up a network of service
centres as well as power outlets for the car all over the city.
And then, there is Pune. A city even more suited for the REVA with
its narrow roads and parking problems!
|