Citroën C5 Goes Twin Turbo
14 February 2008 ·
Citroën C5 Goes Twin Turbo!
Citroen has released the first details of a new twin turbo diesel engine
that will join its Australian range in 2007 on, boasting 125 kW and 370
Nm of torque from just 2.2 litres, making it uniquely light and
powerful, delivering outstanding performance, economy and, thanks to the
standard particulate filter, significant environmental benefits.
This new Citroen engine features several innovations:
* A parallel sequential dual turbo, a world first on a 4-cylinder diesel
engine, designed to boost engine response at low speeds and minimise the
response time of the turbocharging system. Maximum torque of 370 Nm is
available from 1,500 rpm; * A new combustion chamber, the
ECCS (Extreme Conventional Combustion System),
which optimises the air/fuel mix, and a third-generation common rail
system, in which pressure is increased to 1,800 bars for a finer fuel
spray. This combination cuts pollutant emissions and fuel consumption
while improving performance.
Performance from the new Citroën engine is outstanding: one kilometre
in 29.8 seconds from a standing start for the hatchback, and 30 seconds
for the estate.
The parallel sequential dual turbo delivers significant torque at low
engine speeds, doing away with turbo lag. Maximum torque of 370 Nm is
available from just 1500 rpm. In third gear, driver alone, the C5
accelerates from 30 kmh to 60 kmh in 3.6 seconds for the hatchback and
3.7 seconds for the saloon. This is 20 per cent quicker than the
existing C5 HDi.
This system is based on two fixed geometry turbochargers of identical
size. Each one supplies around half the air input required at high
engine speeds. This design principle extends the operating range of the
turbocharger and improves engine performance at both high and low
speeds, particularly during transient conditions.
At low engine speeds, below 2,700 rpm, only one turbocharger is
operational. This low inertia turbocharger delivers instant engine
response, as well as providing up to 40 per cent more torque than the
existing engine.
At engine speeds of more than 2,700 rpm, the second turbocharger
kicks in to supply the increased air intake required at higher engine
speeds. The system is so smart that it starts spinning up the second
turbocharger before plumbing it into the air take system, ensuring both
instant power and a smooth transition to twin turbo operation.
Thus, the twin turbos only work when required, saving fuel and
emissions.
The new engine even looks after pedestrians. It is 40 mm shorter than
the existing engine and this has been used to remove hard spots on the
bonnet, which are critical in making cars safer for pedestrian
accidents.
Full specification and pricing for the new C5 HDi Twin Turbo will be
announced when it goes on sale in Australia in early 2007.
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