Installer's handbook - 1/3 Types of installation - 2/3 Software guide ...

3. UNDERSTANDING
SEQUENT AND
SEQUENT FASTNESS
SYSTEMS
3.1 STRUCTURE
The evolution of SEQUENT
system allows introducing new and
more sophisticated components
trying to obtain higher performance.
The system can be used with
different configurations and different
components (LPG Genius,
CNG Genius. M, LPG MAX Genius,
the new Zenith Reducer, BRC or
Keihin rail, etc.) - Table 1 page 7.
This guide and the Types of
Installation 2/3 one has the aim to
teach the technician the correct and
different use of Sequent and
Sequent Fastness systems.
The SEQUENT systems, starting
from the gas tank to the reducer
included, utilise components,
which are already well known by
the BRC installers. The pressure
reducer, in particular, will be the
GENIUS SEQUENT. It is the same
little-sized reducer of simple installation
already installed on the
Flying Injection, with the difference
that it will be provided with brass
water elbows and a new temperature
sensor, which is not compatible
with the Flying Injection one. The
differences if compared to the previous
conception equipment start
with the rail, connected through the
proper pipe to the GENIUS
SEQUENT outlet, which connects
the gas injectors, supplying them
heated and vaporised gas. A pressure
sensor, that measures the
absolute gas pressure and supplies
injectors, is connected to the rail. If
it is possible to say that the ECU is
the brain of the system, the injec-
tors represent its heart. They are
electro-injectors, whose working
principle is quite similar to the one
of the petrol injectors, but they differ
from these last ones for:
• Larger passage sections, suitable
for the gaseous fuel,
• Lower electric impedance, to
have quick opening times,
• “Peak & hold” electric piloting,
to have small piloting currents
without disadvantaging performances.
At every injector outlet, the gas
is directly introduced, through proper
pipes, in the air-intake manifold,
downstream the throttle valve.
The changeover switch with
level gauge is of the two-position
type, with buzzer. It allows carrying
out the changeover functions from
the petrol-gas and gas-petrol operations,
indicating the gas quantity
present in the tank and moreover
displaying some diagnostic signals
in case of malfunction, lack of fuel,
not correct programming, etc.
Not least, there is the very
powerful, extremely rugged, completely
waterproof FLY SF ECU,
complying with the EMC regulations,
realised with electronic specific
components for automotive use,
which allow to install it even in the
engine compartment. The ECU collects
and elaborates full information
and checks completely the various
system functions; in particular the
injectors, managing the instant
when the injection happens and its
duration with the precision of few
microseconds (microsecond =
1/1000000 of second).
The ECU had been studied to
bear short-circuits of unlimited
duration on each of its inlet/outlet
wires, both towards the ground and
towards the battery positive. It had
been subjected to stringent tests in
order to verify its compliance with
the regulations in the automotive
field.
9
The SEQUENT system communicates
with the outside through a
computer, by means of which, with
a valid and powerful interface program,
it is possible to transfer any
information to the ECU, program
itself, calibrate the system, verify
the correct operation, read and
delete the possible error codes
memorised and have information
about the installation and about the
memory contents of the ECU. The
interface on the computer is therefore
the instrument by means of
which the installer interacts with the
whole SEQUENT system and by
means of which he could “shape”
the gas equipment to fit it to the
vehicle in the different driving conditions.
The tidy collection of all files
related to the different installations
made may constitute a very useful
proper historic archive, both to keep
under control the evolutions of
equipment in the time, and to constitute
a starting point for new
installations.
The guide 3/3 has been entirely
dedicated to the interface program
on computer.
NEW
The new sequential gaseous
injection FASTNESS version
comes from Sequent experience
and is for CNG only.
Based on the SEQUENT consolidated
structure, it has new innovations
coming from BRC experience
and recent experimentation with the
aim to make the system stronger,
easy to install and able to solve
even the most difficult problems.
The innovation and changes will
be deeply described in the following
paragraphs of the present guide:
- System components (reducers,
sensors, etc.)
- Software and engine control
(new strategies).
Both components and software
have been studied to obtain the