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New application for Alfa Romeo's Selespeed system reveals the
economy benefits of Alfa's self-shifting manual gearbox
The Fiat Multipla, already one of the world's most
unusual people movers from its exterior design to its space frame construction
and its two rows of three seats, has now become the first electro/combustion
engine hybrid people mover in the world. All existing hybrids are small cars
but Fiat have recognized that while the environment needs clean cars, the
market still needs the ability to carry more than four adults and their
luggage.
The new people mover also features the latest
application of the unique self shifting manual Selespeed gearbox used in the
Alfa Romeo 156 Selespeed, revealing another
feature of the Selespeed system: Its big fuel economy advantage over
conventional self shifting gearboxes. This is thanks to the fact that while it
shifts its own gears, it retains the fuel economy of a manual because it does
not suffer from the power-sapping losses of a torque converter, the additional
weight and, in some cases, the reduced number of gear ratios.
These fuel economy savings are just as applicable
to the Alfa Romeo 156 Selespeed and reveal another aspect of Alfa Romeo's
unique Formula One derived technology.
The future of motoring is difficult to predict.
Manufacturers have now come up with so many different ideas that we should
theoretically be able to produce a car able to meet different and often
conflicting needs. In other words, emissions that are low in all situations and
very low (or better still non-existent) around town; great range; performance
on a par with present-day cars; load-carrying capacity; better comfort and
safety.
Yet this aim is difficult to achieve because the
challenge to engineers is considerable.
Now we welcome the Fiat Multipla Hybrid Power,
i.e. the very latest development within the minimum environmental impact field.
The car is the result of enthusiastic research and development work to achieve
ecological aims. It draws on state-of-the-art engineering to achieve
ambitiously low exhaust emission and fuel consumption goals.
All the credit goes to Fiat Auto designers, who
have exploited the possibilities of a dual electric and internal combustion
drive system in an original, innovative way.
Firstly they reduced fuel consumption (6.8 l/100
km compared with a figure of 8.6 recorded over a combined cycle for the same
car fitted with a petrol engine only) while simultaneously slashing emissions
by an average of 50% in hybrid mode.
Secondly they ensured true flexibility of use.
The Fiat Multipla Hybrid Power is the only car of
this type capable of electric propulsion alone when necessary. Around town, the
car behaves like a ZEV (Zero Emission Vehicle), has a top speed of 80 km/h and
a range of more than 80 km. Out of town and on the motorway, it is driven by
the petrol engine and electric engine working in tandem and offers the same
performance as (but much lower emissions than) any conventional car: top speed
of over 155 km/h, 400 km range.
All this comes from a car not very different from
currently available versions of the Fiat Multipla, i.e. with the same luggage
capacity, five comfortable seats and unaltered safety and comfort attributes.
From an engineering viewpoint, these results
have been achieved by developing a sophisticated electronic system that manages
(and gets the most out of) both power units: a petrol-driven 1.6 16v Torque
engine with a power output of 76 kW (103 bhp) and a torque of 14.7 kgm (144
Nm); and an alternating current electric engine (asynchronous, triple phase)
with a maximum power output of 30 kW (15 kW direct current) and a maximum
torque of 130 Nm (13.02 kgm).
The car's equipment list also includes:
- An inverter, i.e. a converter that converts
direct current from the battery to three-phase alternate current;
- The batteries, 15 innovative Nickel-Hydride
units that provide an overall energy output of 19 kWh;
- The DC-DC converter that converts drive
battery direct current from 220 V to 12 V;
- An on-board battery charger used to recharge
the accumulators by connecting them to the mains electricity supply;
- A robotised gearbox from the Alfa Romeo 156
Selespeed that controls gear selection and shifts in fully automatic manner,
with great benefits in terms of fuel consumption and comfort.
- It was obviously a technically complex task to
ensure both mechanical and electric systems worked efficiently and also to
ensure the management software did its job properly.
For the person behind the wheel, however, the
Multipla Hybrid Power is an easy car to use. The driver can change modes at any
time by simply turning a knob on the console between the front seats. Each of
the three available options corresponds to a different car operating mode:
'electric', 'hybrid' or 'electric with recharging'.
Electric is the mode where the petrol engine is
turned off and disconnected from the gearbox. In this case, drive comes only
from the electric engine. This option is ideal around town because the driver
can bring the car to the edge of town using the petrol engine and then switch
to electric mode: a bit like changing cars while still staying at the wheel of
your Multipla.
Hybrid is the mode where both engines act in
parallel on the wheels. The electric power unit, in particular, cuts in during
start-up (when it works alone to make the most of its high torque) and during
pick-up and acceleration when it adds its torque to that of the petrol engine.
During deceleration and braking, it recovers kinetic energy to recharge the
batteries. Because the car works in this way while in hybrid mode, emissions
fall in direct proportion to speed. Emissions are therefore lowest of all where
the environmental benefits are greatest, i.e. in town traffic.
Electric with recharging is the mode where the
Multipla Hybrid Power is driven by the electric engine while the petrol engine
stays on at a stationary speed to operate the alternator and recharge the
batteries. This option is useful when you wish to increase the car's range but
do not have an immediate opportunity to connect to the mains.
The Fiat Multipla Hybrid Power is thus
environmentally friendly in all service conditions and actually becomes a zero
emissions car around town. It is a good answer to future traffic needs because
it offers new functions without detracting from the car's original performance
(comfort, interior space, safety, speed, range).
It is also a highly sophisticated car
from a technical viewpoint and ten examples have been produced so far. The cars
will operate within the city of Naples as part of the Atena Project (Ambiente
Traffico Telematica Napoli - Naples Telematic Traffic Environment). The city
will have the opportunity - with the aid of Fiat Auto - to test the vehicle in
the field and assess its practicality and environmental impact in different
situations.
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