place for a carís fuel tank is beneath the rear seats, but in
the compact interior of the iQ this would make it impossible for
Toyota to achieve its goal of a sub-three-metre long car with
four seats. The solution was to create a flat fuel tank,
positioned beneath the vehicle floor.
This was no
simple task, requiring a number of fundamental engineering
challenges to be met. Traditionally a flat fuel tank has been
considered too difficult to design, because of the variance in
fuel level that would occur, for example when the vehicle is
parked on a slope.
persevered with its efforts to make the tank smaller and
calculate the optimum location of its functioning parts. A
horizontal fuel pump was successfully developed, and the fuel
level indicators were positioned in the centre of the tank to
ensure a consistently accurate read-out is given.
The result is
a flat fuel tank, just 120mm tall. Its size and shape mean it
can be located under the floor, which not only frees up more
cabin space but also gives iQ a lower centre of gravity,
contributing to its excellent stability and fun-to-drive
character. It also allows the rear wheels to be placed 440mm
further forward, with shock absorbers cleverly angled backwards
to prevent any encroachment on the rear seat space.
The space in
the rear of the cabin that would usually be taken up by the fuel
tank makes room for two seats Ė the one behind the front
passenger suitable for an adult, the other, behind the driver,
for a child or for extra luggage space. There is extra concealed
storage beneath the seats, while the seats themselves can be
individually folded down to create more luggage room.
The fuel tank
has a 32-litre capacity, enough to give iQ a driving range of
more than 430 miles.